Hi, I've been seeing the same behavior for the past few weeks (months?), but didn't get around to debugging it. Symptoms match pretty exactly: closing the lid leads to a logout (session crash?); suspending via power button does not.
Superficially, this seems considerably more likely to be related to gdm/gnome-screensaver/gnome-session than to systemd. Just installed a new system, restored a few user config files from backup (including ~/.config/dconf) and the issue popped up again. My suggestion would be to reopen and reassign this to a gnome package, so we can keep digging. BTW: my setup is a pretty vanilla wayland gnome session on an intel card. Cheers, Leo
