Firefox on Debian stable is so old that websites yell at you to upgrade to a newer browser. And last time I tried installing Debian testing (or was it debian unstable?), the installer shat itself trying to make the bootloader. After I got it to boot, apt refused to work because of a missing symlink to busybox. Why on earth do they even need busybox if the base install already comes with full gnu coreutils? I remember Debian as the distro that Just Wroks(TM), when did it all go so wrong? Is anyone else here having similar issues, or am I doing something wrong?
I'm considering moving to Debian Stable plus Flathub for graphical desktop packages like Firefox, it works well on the Steam Deck. SteamOS also provides Distrobox which helps in some cases.
Flatpak is awesome, I love it so much. It lets users pick a distro based on the unique features that distro provides, without having to worry about whether their favourite apps are packaged. Since you're considering switching to debian+flatpak, here is a list of pitfalls I've run into in flatpak so far, maybe this can save you some troubleshooting:
.htmlfile that references a.cssfile in the same directory with a flatpak'd browser will be broken, unless you manually make an exception using Flatseal orflatpak override.umountcommands won't propagate into flatpak's sandbox, and drives will get stuck in a weird state where they're mounted in some namespaces, but not others. This should be the default in Debian tho.Anyway, this is just my experience running Flatapk in Void, hopefully it works smoother for you on Debian.