Installing kernel 5.11.0-0.rc4.129 from the rawhide-kernel-nodebug repository seems to have put me back into working condition, more or less the same state I was in under version 5.9.11-200.
Unfortunate that there was a breakage at all. Hopefully there isn’t a regression before 5.11 is cut.
Yeah, I’d like to get multiple high-end graphics cards to everyone on our kernel and QA teams so we’d catch these things (seriously, no snark intended) but it just isn’t practically possible. So the best thing is for the community to help by running with updates-testing enabled and then noting serious regressions in our update system (like this update for 5.10.9-201). That way, they can be caught before the release to the main testing repo, and hopefully fixed for everyone.
One of the main linux graphics subsystem maintainers has this to say:
Those are Navi based, should be good out of the box on f33, but there are no guarantees because graphics drivers like to regress when you turn your back on them