You might not have noticed, but check for the button called "Extra Dim" in your Samsung top area quick controls. It's not enabled by default but allows toggling additional dimming. You can customise it in settings to control the level of dimming, adding a a screen or key shortcut, and control whether it activates on phone reboot or not. Key shortcut (or deactivate on reboot) can be helpful if you set it way up, and have adaptive brightness off, and it is a sunny day.