QxR 1080p vs 4K

What will be better to watch on a 4K TV that supports HDR? I’ve read lots of conflicting information on the resolution and bitrate between the two and how theoretically the bitrate of the 4K needs to be considerably higher to have the same quality as the 1080p.

A lot of movies there is a 1080p BluRay x265 version and also a 2160p BluRay x265 HDR version. Generally which one will look better, specifically for QxR uploads?