diff --git a/pyproject.toml b/pyproject.toml
index cf8be68a4cc..a108f81b692 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -54,7 +54,6 @@ dependencies = [
     "psutil",
     "pyarrow",  # extra dependency for pandas (parquet)
     "pydantic > 2",
-    "PyQt5",
     "python-dateutil",
     "python-multipart",  # extra dependency for fastapi
     "pyyaml",
diff --git a/src/ert/gui/ertwidgets/searchbox.py b/src/ert/gui/ertwidgets/searchbox.py
index 6b2afd596f0..3fec8c17563 100644
--- a/src/ert/gui/ertwidgets/searchbox.py
+++ b/src/ert/gui/ertwidgets/searchbox.py
@@ -63,7 +63,7 @@ def focusOutEvent(self, arg__1: QFocusEvent) -> None:
         self.exitSearch()
 
     def keyPressEvent(self, arg__1: QKeyEvent) -> None:
-        if arg__1 is not None and arg__1.key() == Qt.Key.Key_Escape:
+        if arg__1.key() == Qt.Key.Key_Escape:
             self.clear()
             self.clearFocus()
         else:
diff --git a/src/ert/gui/main.py b/src/ert/gui/main.py
index 2d4e461364d..d8d1776a30f 100755
--- a/src/ert/gui/main.py
+++ b/src/ert/gui/main.py
@@ -139,7 +139,6 @@ def continue_action() -> None:
             continue_action,
             plugin_manager.get_help_links() if plugin_manager is not None else {},
         )
-        suggestor.notifier = main_window.notifier
         return (
             suggestor,
             ert_config.ens_path,
diff --git a/src/ert/gui/model/node.py b/src/ert/gui/model/node.py
index 90e051fb642..ef4ffc3f421 100644
--- a/src/ert/gui/model/node.py
+++ b/src/ert/gui/model/node.py
@@ -1,8 +1,7 @@
 from __future__ import annotations
 
-from abc import ABC, abstractmethod
+from abc import ABC
 from dataclasses import dataclass, field
-from typing import cast
 
 from PySide6.QtGui import QColor
 
@@ -10,43 +9,42 @@
 
 
 @dataclass
-class Node(ABC):
+class _NodeBase(ABC):
     id_: str
-    parent: RootNode | IterNode | RealNode | None = None
-    children: (
-        dict[str, IterNode] | dict[str, RealNode] | dict[str, ForwardModelStepNode]
-    ) = field(default_factory=dict)
     _index: int | None = None
 
-    def __repr__(self) -> str:
-        parent = "no " if self.parent is None else ""
-        children = "no " if len(self.children) == 0 else f"{len(self.children)} "
-        return f"Node<{type(self).__name__}>@{self.id_} with {parent}parent and {children}children"
 
-    @abstractmethod
-    def add_child(self, node: Node) -> None:
-        pass
+def _repr(node: _Node) -> str:
+    parent = "no " if node.parent is None else ""
+    children = "no " if not node.children else f"{len(node.children)} "
+    return f"Node<{type(node).__name__}>@{node.id_} with {parent}parent and {children}children"
 
-    def row(self) -> int:
-        if not self._index:
-            if self.parent:
-                self._index = list(self.parent.children.keys()).index(self.id_)
-            else:
-                raise ValueError(f"{self} had no parent")
-        return self._index
+
+def _row(node: _Node) -> int:
+    if not node._index:
+        if node.parent:
+            node._index = list(node.parent.children.keys()).index(node.id_)
+        else:
+            raise ValueError(f"{node} had no parent")
+    return node._index
 
 
 @dataclass
-class RootNode(Node):
+class RootNode(_NodeBase):
     parent: None = field(default=None, init=False)
     children: dict[str, IterNode] = field(default_factory=dict)
     max_memory_usage: int | None = None
 
-    def add_child(self, node: Node) -> None:
-        node = cast(IterNode, node)
+    def add_child(self, node: IterNode) -> None:
         node.parent = self
         self.children[node.id_] = node
 
+    def row(self) -> int:
+        return _row(self)
+
+    def __repr__(self) -> str:
+        return _repr(self)
+
 
 @dataclass
 class IterNodeData:
@@ -55,16 +53,21 @@ class IterNodeData:
 
 
 @dataclass
-class IterNode(Node):
+class IterNode(_NodeBase):
     parent: RootNode | None = None
     data: IterNodeData = field(default_factory=IterNodeData)
     children: dict[str, RealNode] = field(default_factory=dict)
 
-    def add_child(self, node: Node) -> None:
-        node = cast(RealNode, node)
+    def add_child(self, node: RealNode) -> None:
         node.parent = self
         self.children[node.id_] = node
 
+    def row(self) -> int:
+        return _row(self)
+
+    def __repr__(self) -> str:
+        return _repr(self)
+
 
 @dataclass
 class RealNodeData:
@@ -80,21 +83,36 @@ class RealNodeData:
 
 
 @dataclass
-class RealNode(Node):
+class RealNode(_NodeBase):
     parent: IterNode | None = None
     data: RealNodeData = field(default_factory=RealNodeData)
     children: dict[str, ForwardModelStepNode] = field(default_factory=dict)
 
-    def add_child(self, node: Node) -> None:
-        node = cast(ForwardModelStepNode, node)
+    def add_child(self, node: ForwardModelStepNode) -> None:
         node.parent = self
         self.children[node.id_] = node
 
+    def row(self) -> int:
+        return _row(self)
+
+    def __repr__(self) -> str:
+        return _repr(self)
+
 
 @dataclass
-class ForwardModelStepNode(Node):
-    parent: RealNode | None
+class ForwardModelStepNode(_NodeBase):
+    parent: RealNode | None = None
     data: FMStepSnapshot = field(default_factory=lambda: FMStepSnapshot())  # noqa: PLW0108
+    children: None = None
+
+    def add_child(self, _: _NodeBase) -> None:
+        raise RuntimeError(f"Can not add children to {self.__class__.__name__}")
+
+    def row(self) -> int:
+        return _row(self)
+
+    def __repr__(self) -> str:
+        return _repr(self)
+
 
-    def add_child(self, node: Node) -> None:
-        pass
+_Node = RootNode | IterNode | RealNode | ForwardModelStepNode
diff --git a/src/ert/gui/model/snapshot.py b/src/ert/gui/model/snapshot.py
index 828cace3e40..70bc8a0a3ed 100644
--- a/src/ert/gui/model/snapshot.py
+++ b/src/ert/gui/model/snapshot.py
@@ -3,7 +3,7 @@
 from collections.abc import Sequence
 from contextlib import ExitStack
 from datetime import datetime, timedelta
-from typing import Any, Final, overload
+from typing import Any, Final, cast, overload
 
 from PySide6.QtCore import (
     QAbstractItemModel,
@@ -52,9 +52,9 @@
 IsFMStepRole = UserRole + 10
 StatusRole = UserRole + 11
 
-DURATION = "Duration"
+DURATION: Final[str] = "Duration"
 
-FM_STEP_COLUMNS: Sequence[str] = [
+FM_STEP_COLUMNS: Final[Sequence[str]] = [
     ids.NAME,
     ids.ERROR,
     ids.STATUS,
@@ -295,12 +295,16 @@ def rowCount(
     ) -> int:
         if parent is None:
             parent = QModelIndex()
-        parent_item = self.root if not parent.isValid() else parent.internalPointer()
+        parent_item = (
+            self.root
+            if not parent.isValid()
+            else cast(RootNode | IterNode | RealNode, parent.internalPointer())
+        )
 
         if parent.column() > 0:
             return 0
 
-        return len(parent_item.children)  # type: ignore
+        return len(parent_item.children)
 
     @overload
     def parent(self) -> QObject: ...
@@ -313,10 +317,13 @@ def parent(
         if child is None or not child.isValid():
             return QModelIndex()
 
-        parent_item = child.internalPointer().parent  # type:ignore
+        parent_item = cast(
+            IterNode | RealNode | ForwardModelStepNode, child.internalPointer()
+        ).parent
         if parent_item == self.root:
             return QModelIndex()
 
+        assert parent_item
         return self.createIndex(parent_item.row(), 0, parent_item)
 
     @override
@@ -331,7 +338,7 @@ def data(
         if role == Qt.ItemDataRole.TextAlignmentRole:
             return Qt.AlignmentFlag.AlignCenter
 
-        node: IterNode | RealNode | ForwardModelStepNode = index.internalPointer()  # type:ignore
+        node = cast(IterNode | RealNode | ForwardModelStepNode, index.internalPointer())
         if role == NodeRole:
             return node
 
@@ -343,7 +350,7 @@ def data(
             return isinstance(node, ForwardModelStepNode)
 
         if isinstance(node, ForwardModelStepNode):
-            return self._fm_step_data(index, node, role)
+            return self._fm_step_data(index, node, Qt.ItemDataRole(role))
         if isinstance(node, RealNode):
             return self._real_data(index, node, role)
 
@@ -408,7 +415,7 @@ def _real_data(
     def _fm_step_data(
         index: QModelIndex | QPersistentModelIndex,
         node: ForwardModelStepNode,
-        role: int,  # Qt.ItemDataRole
+        role: Qt.ItemDataRole,
     ) -> Any:
         node_id = str(node.id_)
 
@@ -437,9 +444,9 @@ def _fm_step_data(
 
         if role == Qt.ItemDataRole.DisplayRole:
             data_name = FM_STEP_COLUMNS[index.column()]
-            if data_name in {ids.MAX_MEMORY_USAGE}:
+            if data_name == ids.MAX_MEMORY_USAGE:
                 data = node.data
-                bytes_: str | None = data.get(data_name)  # type: ignore
+                bytes_ = cast(str | None, data.get(data_name))
                 if bytes_:
                     return byte_with_unit(float(bytes_))
 
@@ -448,7 +455,7 @@ def _fm_step_data(
                     return "-"
                 return "View" if data_name in node.data else None
 
-            if data_name in {DURATION}:
+            if data_name == DURATION:
                 start_time = node.data.get(ids.START_TIME)
                 if start_time is None:
                     return None
diff --git a/src/ert/gui/simulation/run_dialog.py b/src/ert/gui/simulation/run_dialog.py
index 1a0e7479cac..2fbb6aeaaba 100644
--- a/src/ert/gui/simulation/run_dialog.py
+++ b/src/ert/gui/simulation/run_dialog.py
@@ -39,7 +39,7 @@
 from ert.gui.ertnotifier import ErtNotifier
 from ert.gui.ertwidgets.message_box import ErtMessageBox
 from ert.gui.model.fm_step_list import FMStepListProxyModel
-from ert.gui.model.node import Node
+from ert.gui.model.node import IterNode
 from ert.gui.model.real_list import RealListModel
 from ert.gui.model.snapshot import (
     FM_STEP_COLUMNS,
@@ -306,7 +306,7 @@ def on_snapshot_new_iteration(
     ) -> None:
         if not parent.isValid():
             index = self._snapshot_model.index(start, 0, parent)
-            iteration = cast(Node, index.internalPointer()).id_
+            iteration = cast(IterNode, index.internalPointer()).id_
             iter_row = start
             self._iteration_progress_label.setText(
                 f"Progress for iteration {iteration}"
diff --git a/src/ert/gui/simulation/view/progress_widget.py b/src/ert/gui/simulation/view/progress_widget.py
index bd5508eefa3..ca721f06b7f 100644
--- a/src/ert/gui/simulation/view/progress_widget.py
+++ b/src/ert/gui/simulation/view/progress_widget.py
@@ -1,8 +1,6 @@
 from __future__ import annotations
 
-from typing import Any
-
-from PySide6.QtGui import QColor
+from PySide6.QtGui import QColor, QResizeEvent
 from PySide6.QtWidgets import (
     QFrame,
     QHBoxLayout,
@@ -16,7 +14,7 @@
 
 class ProgressWidget(QFrame):
     def __init__(self) -> None:
-        QFrame.__init__(self)
+        super().__init__()
         self.setFixedHeight(70)
 
         self._vertical_layout = QVBoxLayout(self)
@@ -109,5 +107,5 @@ def update_progress(self, status: dict[str, int], realization_count: int) -> Non
             self.stop_waiting_progress_bar()
         self.repaint_components()
 
-    def resizeEvent(self, event: Any = None) -> None:
+    def resizeEvent(self, event: QResizeEvent) -> None:
         self.repaint_components()
diff --git a/src/ert/gui/suggestor/suggestor.py b/src/ert/gui/suggestor/suggestor.py
index b7c8359eb24..6a2ae7d99a8 100644
--- a/src/ert/gui/suggestor/suggestor.py
+++ b/src/ert/gui/suggestor/suggestor.py
@@ -20,8 +20,6 @@
     QWidget,
 )
 
-from ert.gui.ertnotifier import ErtNotifier
-
 from ._colors import BLUE_TEXT
 from ._suggestor_message import SuggestorMessage
 
@@ -113,7 +111,6 @@ def __init__(
         deprecations: list[WarningInfo],
         continue_action: Callable[[], None] | None,
         help_links: dict[str, str] | None = None,
-        notifier: ErtNotifier | None = None,
     ) -> None:
         super().__init__()
         self._continue_action = continue_action
@@ -134,7 +131,6 @@ def __init__(
         self.setStyleSheet(f"background-color: {LIGHT_GREY}; color: black")
         self.__layout.setContentsMargins(32, 47, 32, 16)
         self.__layout.setSpacing(32)
-        self.notifier = notifier
 
         data_layout = QHBoxLayout()
         data_widget.setLayout(data_layout)
diff --git a/tests/ert/unit_tests/gui/simulation/view/test_realization.py b/tests/ert/unit_tests/gui/simulation/view/test_realization.py
index 015fb83f578..8f35c5e25e2 100644
--- a/tests/ert/unit_tests/gui/simulation/view/test_realization.py
+++ b/tests/ert/unit_tests/gui/simulation/view/test_realization.py
@@ -12,7 +12,7 @@
     FORWARD_MODEL_STATE_START,
     REALIZATION_STATE_UNKNOWN,
 )
-from ert.gui.model.node import Node
+from ert.gui.model.node import _Node
 from ert.gui.model.snapshot import SnapshotModel
 from ert.gui.simulation.view.realization import RealizationWidget
 from tests.ert import SnapshotBuilder
@@ -104,7 +104,7 @@ def test_selection_success(large_snapshot, qtbot):
 
     def check_selection_cb(index):
         node = index.internalPointer()
-        return isinstance(node, Node) and str(node.id_) == str(selection_id)
+        return isinstance(node, _Node) and str(node.id_) == str(selection_id)
 
     with qtbot.waitSignal(
         widget.itemClicked, timeout=30000, check_params_cb=check_selection_cb