Reports I read stated that while you can select it with SwitchResX it was scaled.

I never tried installing it myself because I’m not a fan of modifying the system on a Mac, especially one I don’t own.

From my poking around I think the horizontal resolution is the problem. The system scans possible resolutions to see what works. Apple just never expected a single display that wide.

There’s some reports that newer MacBooks with discrete graphics on Catalina can indeed run this resolution. It used to not work regardless of hardware, now apparently discrete graphics MacBooks can run it. Maybe because they updated the drivers/system for their new super fancy monitors.