I dont know if you have it in the USA but this device is pretty good:
https://www.truecall.co.uk/shop/truecall-call-blocker
You connect it to the phone line and it answers the calls and asks people who they are. At that point it lets the actual phone ring and then it tells you who is calling and do you want to accept the call or block?
Most spammers will not say who they are and just hang up.
Over time it builds up a whitelist of who to just let straight through
Its very simple