Raspberry Pi on Raspberry Pi: It’s good enough to run its own launch website with tens of millions of visitors | Mythic Beasts https://blog.mythic-beasts.com/2019/06/22/raspberry-pi-on-raspberry-pi/
Since I disabled @conexantsystems's awful Flow.exe (by renaming it _Flow.exe so the Conexant drivers can't find it), I can run @firefox again. It's an ugly hack, but it's all that works in Windows 10.