Roku TV Update 15.0.4 Breaks Brightness Settings"

After the Roku TV update 15.0.4, there's no change to the brightness settings (lowest, low, normal, etc.). I've already performed a factory reset, and the problem persists. I've tried contacting support, but they haven't offered a solution or acknowledged the issue. It's a real shame; I wouldn't recommend the Roku TV system at all. They don't listen to their users