Summary

This is really a remix of semac's (https://www.thingiverse.com/semac/designs) "Iphone 13 and 13 pro lego case" which is no longer on Thingiverse but was downloadable at https://archive.org/details/thingiverse-4967462 and appears to be available here (https://cults3d.com/en/3d-model/gadget/iphone-13-and-13-pro-lego-case-journalthedream ) as well.

The first thing you'll note about semac's design is that it claims to be for iPhone 13 and iPhone 13 Pro, which is impossible. After shaving off the Lego studs and resizing it slightly, It fits the iPhone 12, buttons and all, perfectly (I remixed it into the Lego iPhone 13 Magsafe Case here: https://www.thingiverse.com/thing:5333388). Then I added studs per my other Lego iPhone cases and then added a keyhole to support MagSafe charging using an Anker 7.5W Magnetic Wireless Charger, which is slightly larger than the Apple MagSafe charger at half the price.

I've included files for the shell (no studs), the shell MagSafe version, a full-Lego back, and the Lego MagSafe version.

Print studs down. You'll probably have to run a "fix model" depending on your print software. Should print fine. Would love to remesh this to clean up the internals, but that's outside of my skillset.