Those are the only instructions I need to run to have a fully working Pipewire setup that is compatible with PulseAudio, Jack and ALSA:
$ yay -Rcns pulseaudio-jack
# note that pipewire-jack-dropin is an AUR package
$ yay -S pipewire-{jack,jack-dropin,alsa,pulse}
$ systemctl --user enable pipewire pipewire-pulse pipewire-media-session
$ systemctl reboot
# done