A:Answer That's not a simple answer. Apple likes to use pixel binning to make the screen look smoother while using lower resolutions to make sure everything is readable. However, they will only do this on the monitors made specifically for Apple. Every other 3rd party monitor will display at their native resolution, unless you change the setting manually.
It has been my experience that you do not want macOS to display at the native 4K resolution, or you will find the menubar very hard to read.
