I used to host my own email, but eventually moved to Fastmail. I have to communicate with a number of professionals that work for companies using fairly aggressive third party archiving and filtering solutions (for example, Proofpoint). Keeping my email server on long-term clean IPs in ranges where one other customer didn’t ruin the entire range became a real hassle.
Several such of the larger providers in that space won’t allowlist single IPs if you can’t prove administrative control of the subnet. Alas, I don’t have my own network allocation.
Part of me misses self-hosting. Part of me is glad that I don’t have to manage that anymore, given the growing number of other services, hosts, and network space I manage.