I use an external usb wifi adapter. For ages I was able to always have the external adapter connect to my home wifi, while the internal wifi ran the astroberry hotspot. (I find it useful to have both, in case I need to troubleshoot something).
In the past couple of months, however, the adapters get assigned differently at bootup sometimes. I have to stop and check which is which, change the interfaces' priorities if needed and reboot (hoping, of course, the adapters don't flip-flop again). This is not associated with changing which port things are plugged in to, as far as I know.
I’m doing the same thing and what I’ve done to tie the settings to a particular device is by setting the Device entry in the advanced network configuration app. I believe this is what you need to do. Seems to work for me
I thought I would check. If you hover the mouse over that Device entry it says it will lock it to the name, the permanent mac address or both. I’ve sort of taken that setting it to wlanX (aa:bb:cc:did:ee) that I’ve ended up with the particular device with that mac address being given that name and used for this network setup. I could be wrong and maybe I should just use the mac address though I’ve not had an instance where the networks haven’t worked (excepting the usual flakiness )
If you want set names you can enable predicable network names using raspi-config then use those to tie the device to you network config.