I guess I’m not the only one finding the LCD screen of the Fairphone 2 too bright in the dark, and I guess the one of the Fairphone 3 as well.
I have tried different things, of which different apps that would reduce the brightness on the screen. Though these apps would not be able to reduce the brightness of the status bar, quick settings and device settings, and if I wanted this I would need a paid app from the play store, which I wanted to avoid.
One day I was playing with the settings of my phone (FP2@LOS 17.1), I discovered you could balance the colours of the phone in the LiveDisplay option (well, I already knew, but I never found this useful). And I thought, if I reduce all colours, then it will reduce the whole display brightness. I tried and… it works, and this time everywhere on the screen! It doesn’t really reduce the screen brightness itself, but sets a darker overlay on the screen, but I believe I can’t have better.
So I now have a settings shortcut to here, and it takes me 10 seconds each time I want to reduce the minimum brightness. A bit longer than other methods, but good enough for me.
So I’m posting this here in case some other people hadn’t thought about it and actually find it useful (I haven’t found it anywhere else). AFAIK the LiveDisplay option is available on LineageOS based ROMs, I don’t know for the others.