That is clearly a problem with the big players rather than with self hosting. It should be pretty clear by now that rejection of legitimate mails is intentional

That is clearly a problem with the big players rather than with self hosting. It should be pretty clear by now that rejection of legitimate mails is intentional. While your argument is justified (I face the same issue), the reality is that we are giving up our freedom under pressure by rent-seekers. I wish the users would resist it more vocally.