feifeipig I'm certainly not an expert as to how these things work, but I imagine the GOS team is worried about committing to too many small changes like that, which makes GOS diverge from AOSP in those areas, as then they would also have to maintain them and make sure they don't break when things change upstream. They aren't a very big team at all, and they always prioritize things like security enhancements.
But I am not sure and do not speak for the GOS team. And to be clear, I'm not saying your problem isn't worth fixing as I don't use adaptive brightness for that very reason