I don't agree with their policy, but it is difficult these days to run your own outbound mail service and not end up in the spam box.

I gave up and pay for Gsuite as an SMTP smarthost so my outbound email isn't tagged as spam. That allows me to still process the inbound on my server if I want.

Obviously doesn't help the privacy concern if that is your motivation for running your own SMTP.

If, however, cost is a consideration, Yandex is an option. They will host SMTP for your domain at no charge. https://yandex.com/support/connect/add-domain.html (assuming Russian hosting is okay for you)