@kbabilinski Problem solved. Even without recompiling my repo app, I now see exactly what I expect. To be extra sure, I uninstalled it, removed all manual code from it that dealt with permissions, did a clean build, installed, and:
- It asked for permission
- It found the floor and showed red and green square as expected
- Showed the right controller model
- Showed a nice visualization on my hands.
One think I also noticed: when the Unity splash screen is showed, the background gets very dark, except for some edges. It never did that before. But if that's the only thing, I'll take it 
I downloaded my unchanged Walk the World app, and it still works - even though I ask explicitly for permission, so apparently that does not interfere with each other. But without recompiling, I even got the controller and the hands. Recompiling without the permission code and the default XR rig, it still worked. And the canvas buttons now also respond to the controller.,
So apparently something went haywire during upgrades. I updated it all the way from 1.4.0 to now 1.8.0. I seem to recall I had a beta in between, but I am not sure anymore. However, factory reset was a breeze. The only thing I found REALLY annoying was the ten foot EULA, but that was because I had forgotten to connect the controller. That was also very easy: just plug it in the device, and it 'knows' it.
Long story short: weird this happens, glad we got to the bottom of this. Cheers!