It could’ve also been a snap issue (we’ve seen an issue recently with the VSCode Snap eating up storage) and IIRC Firefox on Ubuntu is a Snap (by default, obviously you can install it any other way as well but you shouldn’t be expected to).

I’ve been on Fedora for 3 or so years and it has pretty much worked flawlessly (the only exception to that is it used to sometimes have issues with automatically sleeping correctly when I closed the laptop lid, but that hasn’t been an issue for about a year)