In case you are running #postmarketos with #phosh : with the latest packages (pmo 24.12.) the GUI was no longer starting up on my librem5, ending up with the login prompt on the console. The reason is that "phoc" does not know the parameter -v , and removing that entry in /usr/bin/phosh-session brings back the GUI upon a reboot:

exec $SYSTEMD_CAT "${COMPOSITOR}" -v -S -C "${PHOC_INI}" -E "bash -lc 'exec ${GNOME_SESSION} --disable-acceleration-check --session=phosh'"