Please read https://gist.github.com/PowerBall253/2dea6ddf6974ba4e5d26c3139ffb7580
sudo pacman -S pipewire wireplumber xdg-desktop-portal-wlr
# make sure there are no other portals installed/enabled
pacman -Q | grep xdg-desktop-portal-
sudo pacman -S grim slurp
then restart your session.