If you had to choose one, probably go with LibRedirect, since for the most part if one instance goes down there are other ones you can use instead.
Though if you have the cash (and are willing too), I would split donations 30/70 percent for LibRedirect itself and all instances you use/like a lot respectively.
Maybe? normally I set the screen to a low brightness level to reduce burn-in, OLED screens still look plenty bright at levels where LCD screens would straight-up be unreadable. I might need to get used to HDR though...