I managed to replicate it on the that page. It took me a while to figure out where to scroll to, but now I can reproduce it quite reliably.
I don’t think it’s possible to run Gnome on X.org in Fedora 42 (maybe it’s possible with some third-party packages, but I don’t think it’s possible with packages from the official repository). The basic installation definitely does not include an X.org session.
Same.
I couldn’t reproduce the flickering on an external display. However, I only tested it on an old low resolution TV. My internal display is 2.8K panel, and I don’t have an external monitor with a similar resolution to test with. However, @blum8 mentioned that the flickering happens to him also on an external monitor with high resolution.
I think @LBTRS](Profile - LBTRS - Framework Community) mentioned in the second thread that he has a standard display.
Screen keeps flickering on lower brightness - #3 by mathos