As mentioned by WinningYard5086 and LorbySI, unfortunately the rotary encoders / knobs on the Korg are kind of useless for MSFS, because they have endstops (which means you can’t turn them all the way around).
Note that for either controller, you can’t map them directly in the MSFS settings, because they’re MIDI devices. You need an external program: vJoy with FreePIE and AxisAndOhs should work with any MIDI device, while X-Touch-Mini-FS2020 has worked well with my X-Touch Mini.
Whatever you get, if you end up flying a device with a Garmin autopilot, the MobiFlight Event Module is really nice because it allows you to map any Garmin button or knob via SimConnect. AxisAndOhs also does this since the last update, haven’t gotten around to trying it yet though.