That's wild. I'm in the US, and I get maybe 1-2 spam calls a month. I get more spam texts than calls, though not many of those either. I've never done anything special to try to prevent them, so I wonder what the difference is.
Stupidly, AFAICT, none of the phone services bother to auto-delete silent voice messages so I have to manually delete them, each one taking ~6 seconds ("call from One Two Three Five Five Five Six Seven Eight Night at three twenty seven pee em, on friday june twenty sixth ..........." delete. Repeat
(1) he was self-employed, so his business contact info (also his personal info) became public record
(2) he NEVER opted out of anything (eg “type STOP to opt-out”), never told callers to take him off their marketing list, and he was VERY sloppy with handing out his primary contact info on websites (maybe shopping or sweepstakes).
My parents had their number for ~30 years. I never get spam calls or texts. They get one once a week or so (this is in Germany, we get a lot fewer of these calls).