Run it in a restricted VM, which is not joined to AD and cannot talk to it either. PAM will not save you, either will Airlock Digital or something like ATP or anything else like it.

Software for running VMs is free.

> Giving users local admin rights is a massive security risk we can't take.

Sounds like you made your endpoints into pets and bastions, that's an architecture that is guaranteed to fail. Work towards a design where the endpoint no longer matters.