My experience with HDR has been pretty abysmal on a $500 4K TV. Badly tuned HDR is way worse than no HDR at all.
I have 20/20 vision, and I really can't tell the difference between 1080p and 4K for video games and movies. I will never do below 4k again on a desktop, but 1080p is more than fine for a TV. Higher framerate makes a far bigger difference than higher resolution for video games too.
You can see the difference in 4K when the bitrate is there, but most streaming platforms compress their videos too much for it to be worth it. It's definitely not the jump that 720p to 1080p is, though. I agree with everything else you said.
For gaming, the internal render resolution of a gaming console might not go over 1080p anyway. If it's a Switch 1 it might even be only 720p. So if that is the main usage, you are right, a 4k screen is a waste of money.
Whether 4k is worth it depends a lot on the size of the TV vs how far away you sit. For a 65" TV, I don't see much difference between 4k/1080p above ~8ft away.
HDR is indeed effectively a marketing gimmick on many cheap TVs. They are getting better though
Also the content being viewed. High bandwidth 1080p can look sharper than over-compressed 4k.
It’s why even non-4k BluRays sometimes look better than streaming.