I have this set up at twilio with a simple Studio workflow and so far it defeats 100% of automated dialers:

A lot of auto-dialers wait to hear a human, so to trigger anything listening for a response, the challenge goes "Can you hear me? This number is protected by Samaritan Call Protection" (shout-out to Person of Interest)

Then about a second later, it follows "Press 5 to be connected."

Things that dial 5 get a ring-through to my cell, things that don't get blackholed.