Old chair mat is out. Ran the rubber rake through to remove as much hairballs and other fallen crap (fallen sausage bits, foam pieces from degrading chair armrests, etc.) and… yeah, that’s as good as it’s gonna get.
Cracked chair mat turned out to be about 30% of my frustrations with this demon chair. On carpet, the demon chair is immobile when occupied, which I’m fine with! I take it it will be like this with the new chair unless I get a new chair mat (not bloody likely).
Now we just have to fix this thing about me randomly falling asleep in this thing for hours at a stretch…