I send mail directly. I have a public IP address. I had to remove it (a few times) from a list of ‘dynamically residential address space’. I have configured the server carefully and implemented SPF, DKIM and DMARC. I have proper revDNS records. Currently my mail doesn’t seem to be considered SPAM by Google or others more often than other mails.

When filters consider some mail spam there usually is a reason. The trick is to find the reason and understand how to mitigate it. Some anti-spam measures are not fair (like blanket blocking whole countries or ISPs), but I was lucky enough not to be bothered by those.

It is not that bad. I have been running my own mail server for 20 years and i generally don’t have more problems with it than users of ‘big and known’ mail server do (it is not like GMail is perfect). And when there are problems I am usually able to tell what happened.

But this does not mean I would recommend self-hosting mail server to everybody. I am an expert, have been doing this professionaly for years. And it is an ongoing fight. It is not like I set it up in 2000 and it has been working since then without changes or incidents.