All spam-blocking apps work the same way (with the exception of Google products like Call Screen) and they’re typically useless due to things like number spoofing.

I just use Fossify Phone or whatever to send all unknown callers directly to voicemail.

reading the description, it’ll be most effective in the US because of the STIR attestation being one of the criteria. other than that, it’ll probably work as well as the rules you configure.

Get a phone number from a area code you don’t know anyone in (montana for example), route all calls from that area code to voice mail, never ring. 99% of spam is solved.