The XboxOne S is still dimming and going dark when watching Netflix and Movies

I mean when the screen dims when it goes into idle. When i watch a movie or tv the screen dims

Did you have an Xbox 360, pkvas? The screen never dimmed while watching movies of any sort (Dvd, Netflix, Streaming media from PC..etc). It's only when idle and no action at all that it goes dim. If the 360 has the feature, why not carry that over to
the Xbox One. It's a pretty big deal for a lot of people. You might not understand it completely, but it is.

I mean when the screen dims when it goes into idle. When i watch a movie or tv the screen dims

Check the settings on the TV with the TV remote Menu.

I also just this evening started having this issue. Things were fine with Netflix at 4pm, played a game for a couple hours, had dinner, came back to watch something then Netflix stared going dim after about 15-20 minutes. Also, noticed when the dimming began
happening that the wireless control no longer turns itself off automatically after a period of no use. Don't know if that's related or a separate issue.

No, I'm not in the Xbox Insider Preview program. Would it help?

I did try doing the power cycle thing to no avail. But, now that you mention it, I recently went on a vacation in which I turned the Xbox fully off. When I came back is when I got Endgame and noticed the dimness. I actually also got and watched Alita
right before I left and don't recall dimness there, although the movie is intentionally dark in many scenes so maybe it was dim and I just missed it, not sure. But Cap Marvel came out in June and I'm pretty certain I thought it was vibrant.