The case can be printed out as suggested in “3d print layout.3mf”. Then you can use 4x countersunk self-tappers (this model supports a 4mm thread with an 8mm head diameter) to blind-mount to a surface. For extra security you can then glue and hammer in the plugs. Feel free to use the FreeCAD file to edit the model to suit whatever fasteners you have on hand.
Also here: https://github.com/flightmansam/airtags-stealth-case
The author remixed this model.
Pretty much everything: