Since I started the beta I have been dealing with very low maximum brightness, and last night I discovered last night that under accessibility, I had lowered reduced minimum brightness enabled. Upon disabling it, my screen maximum brightness returned to normal. Obviously this is a bug, as extra dim mode is not supposed to have an effect on the maximum brightness levels and I have reported it, sent in feedback with a system log and all that. However, I just wanted to pass along the solution for it just in case anyone else was dealing with reduced maximum brightness as well.
If extra dim was on, yes, it's going to have an effect on your maximum brightness. Because even if you move the slider you can make it brighter while extra dim is on but it will only get so bright.
I've always had extra dim enabled, and never experienced this in oneui5 or earlier. The entire second half of the brightness bar literally did not increase the visible brightness of the phone. I don't have a oneui5 device with extra dim to verify (just a tab S6 lite), so either there was a change in how it functioned in 6 or there was a bug that jacked up intensity. Either way, I've just created a routine to keep it going at night only.
