Summary

Corne'ish Zen snaps in, the holster clips onto your pocket and supports the zen on your leg. Can be used for standing typing & VR with Oculus Quest.

The FDM versions are recommended for most consumer 3d printers since they're split to minimize overhangs.

Superglue or epoxy the top/bottom together, and add a money clip like https://www.amazon.com/Stainless-SourceTon-Wallet-Credit-Minimalist/dp/B078YQMZXT

Alternately you can print the belt clip, and use that with a quick release belt.