www-client/firefox does not have a pipewire use flag, it uses pulseaudio which can use the pipewire backend for playing the audio (not sure about the specifics) https://wiki.gentoo.org/wiki/PipeWire for all issues, I’d recommend #gentoo on irc.libera.chat

Are you not using a desktop profile? That sets the sane defaults you’re missing

English is just one language of many. Would you change it if it was a slur in french?