In preparation for Bug #2050378, I'm testing in F37. The SDDM Wayland Greeter keeps the screen on all the time when no user is logged in. When a user is logged in, power saving settings work properly. Possibly related are https://github.com/sddm/sddm/issues/1256 and https://github.com/sddm/sddm/issues/1302. Using: sddm-0.19.0^git20230201.3ee57e9-2.fc37.x86_64 sddm-wayland-plasma-5.26.5-1.fc37.noarch
Now using sddm-wayland-plasma-5.27.1-1.fc37.noarch, even when users are logged in, power saving (monitor off) does not work at all.
*** This bug has been marked as a duplicate of bug 2173300 ***