Use the seek bar and tiles in AutoNotification to set brightness level, or prompt for adaptive bright. I kind of miss my HTC it had a little slider like this and a check mark for adaptive brightness. That's the only thing I miss from this device.
Run the set tile task by itself to set the tile initially.
Tap tile once to bring up dialog, double tap to make auto brightness, long press toggles between lowest in highest setting.
requires AutoNotification , Autotools secure settings, long press will require Android 8.
This is a tasker project now.
Automatically set brightness 1.4
Set the brightness level, or set adaptive brightness using a seek bar