I use Qubes OS, when running a lot of VMs with memory limitations the difference in performance becomes noticeable. It's not that Firefox does work, but Firefox becomes sluggish at settings where Brave will run without any problems.
That said, I still use Firefox on Windows and traditional Linux.
Some addons do not work on my Firefox after some updates. Had to switch to Chromium sadly. Around 2 years I switched back to Firefox but I think this time I just stay at Chromium. Seems to be more stable and quicker...