[Bug]: Synchronization/?2-thread Checksum Checking? freezes the UI.

[ghost]

⚠️ Before submitting, please verify the following: ⚠️

• This is a bug, not a question or a configuration issue.
• This issue is not already reported on Github (I've searched it).
• Nextcloud Server and Desktop Client are up to date. See Server Maintenance and Release Schedule and Desktop Releases for supported versions.
• I agree to follow Nextcloud's Code of Conduct

Bug description

The UI isn't separate from the synchronization/checksum checking thread, if there are files and folders present then the synchronization freezes the UI.
...

Steps to reproduce

1. Install nextcloud.
2. Synchronize(turns out later for whatever reason couple folders are empty).
3. Uninstall nextcloud.
4. Install nextcloud back.
   ...

Expected behavior

Just you know being able to use the app, before it verifies 200GB worth of data.
...

Which files are affected by this bug

• irrelevant

Operating system

Windows

Which version of the operating system you are running.

Windows 11

Package

Official Windows MSI

Nextcloud Server version

• not my server

Nextcloud Desktop Client version

3.13.3

Is this bug present after an update or on a fresh install?

Updated from a minor version (ex. 3.4.2 to 3.4.4)

Are you using the Nextcloud Server Encryption module?

Encryption is Enabled

Are you using an external user-backend?

• Default internal user-backend
• LDAP/ Active Directory
• SSO - SAML
• Other

Nextcloud Server logs

No response

Additional info

No response

[joshtrichards]

#5031 perhaps?

Though there are some other possibilities.