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)
Neat, good job. You might want to include what screw size it fits, and the word “anchor” somewhere in the description/title for searching (these are typically called drywall anchors in the US).
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.