Google say 576 megapixels of which only 7 matter.

I don't care enough to link but you can google.

Humans see at roughly 8k per eye, though there are many many caveats to this statement (the TV isn't embedded in your eyeballs for one, you don't see 8k everywhere all at once, etc etc)

Well each jump over the years 480P>720P>1080P I have found to be a considerable and noticeable jump. 1080P>4K does not seem to be that much different in picture detail. So I’m guessing we’re starting to hit some level of diminishing returns for what our eyes can perceive. 4K and HDR do have some noticeable gains in color vividness.

Of course it might become more pronounced on very large screens as each individual pixel is larger and thus imperfections become more noticeable.