Can only screen share the entire screen instead of an specific window

I was trying to screen share just an specific window to Firefox, but the browser wouldn’t let me choose any but the entire screen. Had the same issue with Discord, but apparently the support they offer to their Discord app on Linux is pretty bad so I don’t know if there’s a fix for that. Any help?

On telegram, a fellow user had him install gnome and gnome-extras on a hunch to rule out an XFCE config problem or something.

After logout and login, gnome still had the same problem with not being able to share a window in Google Meet. But still able to share the entire desktop…

Old Manjaro forum post from last year has the same problem, vaguely blames pipewire, yet no solutions.

Anyway, we need community power on this thread with some known experience or hints.