Summary

Plugs for this specific thing only like 3 people are actually using https://www.printables.com/model/897252-raspberry-pi-zero-to-waveshare-pi-3-adapter-case
You can find the top of this case on the link above. If it ever goes down for some reason, I can add the top here as well. (this is my way of contributing to the project I took the bottom from ;) )
Includes remix of the case part itself, removed screw tabs.
Added printed plugs to secure the pi's adapter and lid (no metal screws/bolts needed)
print the plugs with the larger side down, they have been scaled to properly fit without needing to configure x/y expansion or scale. At least on my ender3 it works :p
print with 100% infill on either .18 or .20 layer height,