In my experience the problems with self hosting email mostly occur when something is misconfigured. I think it’s good for people to try to self host it, and if you pull it off it’s great (I love having mine self hosted, and it’s convenient to be able to have as many email addresses, storage, and accounts as I want). It is difficult to get right and debug when something is going wrong, but it’s far from impossible. If you set up SPF, DKIM, and DMARC and have rDNS pointing to your mail server’s domain name you’ll likely find success. It’s possible I’ve just gotten lucky, but I have never had a problem with IP ranges getting banned.