So I have roku streaming stick, and it has amazing colors when I am consuming content from it, TV's picture mode settings works as well (HDR, Movie, etc.), however this setting does not work when I launch apps from my default android tv, no setting in picture settings work other than brightness. Can anyone assist? It has way worse colors than roku.
I'm not sure how very useful this comment will be, but it's maybe worth a look. I found once with a friend's TV that their TV was a 4K "HDR" TV, but the brightness was only capable of 250 nits brightness. For HDR to be effective it required a much brighter display, otherwise it would same that the high dynamic range can't be fully visualised. When they used their Chromecast everything looked great, but using native apps often made everything quite dark and a little dull. The Chromecast was not an HDR capable device and so it didn't attempt to make use of the HDR capabilities whereas some of the native apps did.
What model is your TCL? Maybe you are running into the same issue?