Its even worse when you force Firefox to use wayland its icon doesn’t even show.
Edit: Oh since everyone now is confused; I only have the flatpak version of Firefox installed yet it doesn’t use the pinned icon and doesn’t even use the firefox icon under wayland at all.
Package managers like apt or rpmn(or whatever for your distro) are the standard way to install software. If there’s a good reason to avoid them, OK, but no good reason was stated here.