The thing about self hosting too is that you then own your identity. I have had my own domain and email for 20 years now while many "free" email services have gone away or merged. The problem as you say with difficulty is that due to the centralization of email providers, it is hard to get your outgoing mail accepted everywhere. I now have no problems but it took a while. The worst were Yahoo and Verizon straight up denying my email as spam despite having DKIM/SPF/DMARC set up perfectly. These things too there are subtle problems that can make them invalid such as hostname differences.