It seems that most of the drywall mounts that I looked for printed in a vertical orientation, which is not good for strength.

For once, I didn’t reverse engineer anything to design this. Lulz.

https://www.printables.com/model/548516-printable-drywall-mount

Update 8/10 - Added dimension sketches, Added .step file, Added a thinner support ring option that will sit more flush (but not completely)