Been using an absolutely superb 12-year-old higher-end 58" Samsung Plasma TV. All the Roku boxes that I've used with this set have functioned just fine with exemplary colors, etc. However, when I brought aboard the Paramount + channel, that all changed.
Then I read a reply somewhere that the streaming stick didn't seem to have those issues. So I went on Amazon and got the 2021 streaming stick (4K) and figured I'd give it a try. Not expecting much, to my surprise, it worked and the colors and contrasts all returned. Can't explain it, and as I mentioned in a previous reply, the algorithms that Roku uses in the streaming stick must surely be different from their regular boxes.
But just to be sure, I quickly connected the streaming stick to my other Samsung LCD TV's that I have throughout my house (a 36", 40", 28" and 55") and the streaming stick worked superbly with all of them.
So I don't know what else to say here.