Apparently it's a recent list... EDIT Fwiw, back in June I was trialing Debian 12 and found that any Flatpak browser - Firefox, Chrome, Librewolf - I installed and attempted to run, crashed every time. I ended up installing Snap versions and had no issues at all with them. Deban 12 is out!
Interesting evolution Since you're now running a rolling distro - have you also tried Arch Linux? I'm asking this because I've also tried Tumbleweed (and it's still installed in a VM but I haven't updated it for quite some time) but Arch has always been snappier and leaner for me, and even important security updates on Tumbleweed often arrived days later than on Arch. I know that many people shy away from Arch as its official installation process is not GUI driven (but you learn a lot by doing it this way). However, there is the archinstall package which makes the installation much easier and there is, e.g., EndeavourOS (which isn't supported in the Arch forums, though). It's certainly true that Arch is more of a do-it-yourself distro than most others but you can find an answer for nearly every question in the excellent Arch Wiki which is second to none.
https://ubunlog.com/en/firefox-like-snap-what-to-know-and-alternatives/ It's been known for some time.
Tuxedo OS2 is based on Ubuntu LTS 2204 without Snapd, no telemetry and Firefox in .deb format. Also, it has the latest KDE version (today 5.27.6) and more recent kernels.
Many years ago I successfully installed Arch the old fashioned, hands on way and ran it for a little while. It was incredibly responsive, but it was the difficulty of running Apparmor as well as some sort of buggy behavior, I can't remember what, that lead me to move on to something else. Maybe one day if I get bored of Tumbleweed, I'll try it again