Distance and size makes the most difference.

If you’re sitting ~7’ back from a 50" TV it really doesn’t matter if it’s 720, 1080, 4k, or 8k.

You have to be right up on it to tell or have a huge screen.

Nicer TVs do have better color and contrast that you can tell from any distance. But generally you have to have something to compare it to for it to really matter. Dark scenes on a poor quality TV can look awful.