Wrong
3840x2160 is 8,294,400 pixels
4096x2160 is 8,847,360 pixels
1920x1080 is 2,073,600 pixels
4K via 3840, is 4x times the resolution of 1080p because the resolution is doubled both vertically and horizontally.
If OP is running on a native 4K display, he’s better off running at native 4k with lower graphics preset or any resolution that is between that and 1440p at any graphics settings than running at native 4K.