> They claim to know a lot but then none of them build proper Cf Lumen or F.Lux style tooling (i.e. super easy default instead of requiring tons of setup) for turning ALL blue light off (red shifting) IN THE DEFAULT OS as the primary way to use your device at night.

Probably not what you are aiming for but for Linux this is a somewhat solved problems. The default DM, Gnome, has built-in color shift with a time schedule AFAIK. For Wayland and xorg there are also numerous other solutions that do a display-level redshift, I can recommend wl-sunset for Wayland.