A Google Sheet used as a password manager that every employee had access to. To keep it “secure” the cells with the passwords were hidden by changing the background color to match the text color.

I don’t know how to help with the black screen, but you are on the right track with switching from x11 to Wayland for HDR support.

If you get that resolved, look into gamescope to launch Steam/games using the hdr-enabled flag.

Went through this on opensuse with an AMD build and Wayland + gamescope were the key parts getting it to work for me.