You can now configure different permissions for your delegates in Microsoft Teams. You can set Make and Receive Calls on a per user basis.
For an example: Your personal assistant can make and receive calls on behalf, but like a workmate might only be able to receive calls only.
Another option would be, if you don't want to us a call queue, you could configure a user with delegates making calls on behalf of an e.g. Call Agent but will not be able to be called back.
Navigate to the User Settings / General section and click "Manage Delegates".