Resolution wouldn’t make much difference but other improvements exist that could improve the image quality. If you have moving light and dark next to each other there can be a delay in the pixels changing colour or a bit of light bleeding across from one to the other. There is also how vibrant the range of colours are.

Unfortunately these things are a bit harder to measure and show than resolution.

I’ve got a similar setup. I’ll sometimes even watch stuff in 720p, and it’s fine.

I play games on my steam deck on the couch. When one of my kids was over the other day, she mentored I should play it on the ‘bigger’ screen. I held up the deck - the screen almost exactly overlayed the TV screen.

I used to have a screen with that refresh and when I was tired and tried to read anything on it, my eyes would, like, vibrate? Like visual stuttering. Not a fun experience. Upgraded to a 60hz and that’s the minimum I’d ever consider for any use now.

So yep, definitely not true.

I also prefer 4k for crisp text for similar reasons (e.g. game text). It might not matter for your average movie, but it matters for a lot of normal use if you don’t want to strain your eyes.

Study used a 27 inch monitor

So if 1080 is fine for 27 inch monitor, 4k is fine for the 55 inch tv I have on my desk for a computer monitor.