[dataflow]

> These even pass dmarc/spf/dkim etc, so who knows what's going on here.

Those have nothing to do with being spam, right? Spam is about content, those are about authenticity. Anybody can send authentic trash, or unauthenticated gold.

[mzhaase]

Your spam score goes up without DKIM or SPF.

[dataflow]

Sure but that's just because spammers don't tend to authenticate their email. But that obviously doesn't mean they get to send spam if they do.