Here's my setup. We own a 65" LG G3 and I often game on it. We sit about 4 meters away. I'm a PC gamer and run a 3080. For what it's worth, I have 20/10 vision (although the trade-off is I'm a bit far sighted).

While I can see a difference between 1080p and 4k, it's pretty minimal for both 3D and 2D, to the point where I have to be looking for it. When I'm playing a game, it's not really noticeable at all. It's a bit more noticeable up close but I never have cause to sit just a meter away. This has all been confirmed by my wife and multiple friends and family members who have checked out our setup prior to buying a new television or done the same comparison themselves.

We even did a fun experiment (I'm a scientist so I love experiments). We ran the same game in 4k or 1080p with otherwise identical graphics settings, but with the resolution chosen at random by someone else, and tried to discern the resolution at our normal sitting distance while playing the game as we normally would. The results were equivalent to choosing randomly.

Lastly, a friend was all for buying an 8k television prior to my 1080p/4k demonstration. They now have the even larger 77" version of my television and, at about 5 meters away, the difference is still pretty minimal.

So I happily game at 1080p with the settings cranked up.