Little update on the Maya front.
I completely uninstalled the beta driver. rebooted as the installer wants. Reinstalled the beta driver, rebooted again, installed the plugins. And for now it seems more stable! I have been mucking around in Maya for 10 minutes without it crashing! Not an in depth test, but looking good so far.
But another note, I noticed button mapping for Keystrokes doesn't work anymore. I had a button assigned to SHIFT, which didn't respond, tried the other function keys and none of those work either. BUT! this led me to another revelation. While messing with that menu in the system settings I noticed the various camera modes you can assign to the button through Application Commands in there (I remember those modes being available in a menu option in Maya (called 3DConnexion) before which isn't there anymore. But I tried that to switch between a few modes, which works, pushing the button activates that camera mode. One of the options in the list is lock horizon. Pushing that button locks the horizon to the ground plane of the scene again, making the camera move like before!
So my guess is that was an option in the menu that was in Maya before which I must have switched on a decade ago and have since forgotten about.
So at this point the camera moves like it did before, and Maya hasn't crashed yet, though again, that needs a bit more testing so I'll get back to you on that tomorrow. Right now I'm only experiencing the viewport glitching, but as long as that doesn't crash the app, I can live with that for now
It's time to roll the dice...