Sudo apt install librewolf
Sudo apt install flatpak
Flatpak install librewolf
If that doesn’t work then I recommend you try just installing it from your package manager of choice
But if that doesn’t work then I don’t know what else I can do for you mate. Firefox broke on my version of Linux mint just uninstalled it and used unchromeium Linux and it’s subsequent distros can be quite weird at times
I prefer actioncube