Why is it that when I film in higher resolutions, the colors become much different (better, more natural looking).

I have a sonya6400, and the 4k footage has tremendously bette colors than 1080p footage. And I now just got a new gopro, and I see the same pattern. 4k has much better (more natural) colors than 1080p, and 5,3k is even better than 4k.

I've also tried youtubing some resulotion comparison videos on the same camera (with the same settings), and it's the same. Higher quality nearly always produces better and more natural colors.

What the hell is going on? I would like to not be limited to the highest possible resolution, but I just cannot unsee how bad the colors look on 1080p.