2560 x 1440 with retina resolution on MacOS

[Mac2k]

It would be great to allow full 4k resolution but scaled to appear as 2560 x 1440 on a Mac, with 4k external display.

Currently:
3840 x 2160 icons and text are too small on a 4k display.
1920 x 1080 icons and text are too large on a 4k display.

2560 x 1440 (low resolution) - does not take full advantage of a 4k display resolution.

Thank you