I came up with a pretty bulletproof solution years ago though it is a bit of a nuclear option... (1) change your phone number to somewhere you don't know anyon

I came up with a pretty bulletproof solution years ago though it is a bit of a nuclear option... (1) change your phone number to somewhere you don't know anyone that ideally has a single area code (e.g., north dakota with "701") (2) use some sort of app (e.g., numbershield on iOS) on your phone to block all calls from 701-XXX-XXXX (3) use this new number going forward (or transfer the existing number to google voice which seems to have an effective blocker and have it forwarded to new 701 number now I can confidently pick up all unknown calls especially if they are local to me knowing they are legitimate - I now only get a few spam calls per year since doing this