nekapsuleB

Self hosted doesn’t mean hosted on your home connection. Even with a static IP I would recommend against hosting your mail server at home because any outage means no mail (been there, done that). I have hosted my own imap/smtp server for decades and couldn’t be happier with it, but yes, the smtp part is tricky to evade blocks, especially from MSFT who would just block entire networks without a real reason (Linode for example)

Antispam is easy with a mix of greylisting and spamassassin