Screen does not blank and lock after 5 minutes of inactivity

Using Gnome, SDDM greeter. Gnome settings (Privacy and Security) are to turn the screen off and lock the screen after 5 mins. of inactivity. Screen stays on and the screen does not lock. Maybe it’s because I’m using SDDM instead of GDM? Using version 41450 of Clear Linux with Gnome and KDE desktops. (Update: OK, the screen locking is not supposed to work with Gnome under SDDM but not sure about turning the screen off.)

I tried using GDM instead of SDDM, and it keeps looping back to itself after entering my password. There’s an error message that says: “gkr-pam: unable to locate daemon control file”.

Looking at the journalctl entries for “gdm,” it says it’s not loading the amdgpu driver (I have an amd radeon video card) and gdm is running under x11 instead of wayland.

After more playing around, I’ve concluded that GDM won’t launch KDE and SDDM will launch Gnome except that screen locking and monitor screen turn off won’t work.