Turns out my idea in comment #3 is already implemented in GNOME 48 (Ubuntu 25.04):
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4209/diffs?commit_id=313860e2fab15249337f70d0c298dd02b903c7b9 -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to mutter in Ubuntu. https://bugs.launchpad.net/bugs/2106437 Title: monitors never dpms off when three present To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mutter/+bug/2106437/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs