I receive more spam than legitimate messages on WhatsApp. But I also don't use it a whole lot.

I suspect that, a bit like email addresses, being very selective about who you give your "address" to is the most important bit.

Sadly, phone numbers, unlike email addresses, are such a small address space that it's possible to just message all of them.

Multiple times a week I receive WhatsApp spam. Generally it's trying to add me to a crypto group or someone trying to phish information.

The only other service/medium where I get comparable (really any) spam is SMS/email.

I've never, and I mean never, have received a spam message over iMessage.

I live 10,000km away from the US and can confirm that I get more spam on androids than when using iMessage. It wasn’t the main reason I switched back to iOS with my newest phone but it was a reason.