I send mail from Digital Ocean. I can tell you that neither Apple nor Microsoft give two hoots about any of those if you are on their ASN blocklist. I send lot

I send mail from Digital Ocean. I can tell you that neither Apple nor Microsoft give two hoots about any of those if you are on their ASN blocklist. I send lots of email that is verified with SPF and DKIM to them via relays. But any messages sent directly from "untrustworthy" IP ranges are just blocked with a generic message. This is in contrast to GMail which rightfully treated my first messages as suspicious. But once a handful of users pressed "not spam" they don't care about what IP it comes from anymore as the domain reputation has taken precedence.