This is a feature I'd really like as well, a blue light filter is a must for me on any device with a screen. I've always had problems with f.lux to behave correctly on Linux, so having one built into the OS (as an option of course) would be great.
I used redshift successfully for a time. It worked rather well but I don't know the current state (eg does it support wayland)
Redshift still works quite well. Maybe it should be pre-installed and better 'advertised'. Many people still don't know that this is a very nice feature to have.