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)
Cool, I’ll add better details, for sure!
Fyi, it should work for screws with a diameter of ~3.5mm. As long as you can get the screw to self tap its own threads, you should be OK.
Everything should be a very tight fit, when all is said and done. I have to press the anchor bits into the cap by pressing the assembly together hard on my desk.