The way I usually adjust a TV (I must have read this someplace) is to turn the color down to zero and make the picture black and white (or as close to it as possible). Then adjust the brightness and contrast, so the picture looks about right. And then turn up the color again just enough so the picture looks realistic. Then tweak the brightness and contrast again.
Usually the color adjustment is a lot lower than most people are used to. But I want the picture to look as realistic as possible. Like I'm viewing the scene in real life.
In general, the picture settings on phones and tablets look about right to me. Though, even on my Google Pixel 3aXL, I turned the colors to "Natural". The other settings sere Boosted and Adaptive. (Adaptive was the default.)
If I don't want to start from scratch, I generally just turn down the color until it stops looking radioactive. Then turn up the brightness until the pictures doesn't look too dark. Then I might adjust the contrast so the picture doesn't look too faded.
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Anyway, this seems to work on most older TVs. But when I tried it on my friend's Sony 4K TV, changing those settings barely changed how the TV looked. I think HDR largely locks in the picture. Also when I try to adjust the 4K HDR picture on my niece's TCL Roku TV, it still looks too dark.
Anyway, here's some other guides on how to adjust a TV.
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CNET: If you want better TV, you need to change these picture settings. We'll walk you through how to tweak your TV's color, brightness, picture mode and other settings. It'll make a big difference.
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HelloTech: The Best TV Picture Settings For Every Major Brand (the article doesn't mention any brands)
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Consumer Reports: TV Settings That Deliver the Ultimate Picture Quality. (This article mentions "With some sets, you’re blocked from making some picture-quality adjustments when the TV is in an HDR mode; other TVs give you total control over all the individual settings.")
