I disabled by screensaver so I could leave Half Life Blue Shift running while I made breakfast this morning for a record simultaneous users attempt that someone organized. I left my computer unattended while running Half Life Blue Shift and when I returned an hour later my screens were black and off! I moved my mouse and everything woke up as expected with the game still running.
I'll do some more testing, but this may be a bug with the screensaver & locking behavior in Windows 11 22H2 build 22621.2134