Is there a way to set the gateway in station mode, and add alternative options?

[orvio-craig]

I'm trying to implement a standlong gateway which also has a RAK2287 onboard. I have set the gateway to disable the AP and operate in station mode.
I now want to do a few things:

1. Use an USB wifi dongle as an AP to enable local connections to the device for configuration purposes
2. Use the ethernet port to connect an IP camera, with the endpoint being the RPi

To do this I imagine I need to set the Pi up as a DHCP server on both interfaces, but trying to do so seems to make the system very unstable and it no longer connects as a station.

I used this guide (https://maker.pro/raspberry-pi/projects/how-to-make-a-raspberry-pi-3-hotspot-and-build-a-stand-alone-network) to help me configure it as a WiFi AP substituting the on-board wifi interface (wlan0) with the external one (wlan1).

Is there something else I need to do to make this work?