Hi, email self hoster here, though with a unique circumstance. Self hosting email is fine given you know what you’re doing or have a unique circumstance like I do, I run my own ASN (internet thing allowing you to directly connect with other internet networks like your ISPs) and you can obtain your own IP addresses that you control yourself, meaning you lose the issue of ISPs giving you crap IPs, or your hosting provider being blacklisted because of someone else. I never get sent to spam as a result. Self hosting email is a doable thing, you just need more control over whatever IPs you use than most people will have at home

So self hosting yes, but not for the average person with a residential ISP IP address.