For $400 to $450 USD, the Innocn 27C1U comes with almost everything you'd expect including FreeSync, 4K UHD native resolution, and a surprisingly decent stand with rotating, swivel, and tilting options. Picture-in-picture and an accelerometer are interesting extras, but they could use a bit of work to be more user friendly.
https://www.notebookcheck.net/27-inch-Innocn-27C1U-monitor-integrates-a-gravity-sensor-for-automatic-screen-rotation.597654.0.html