So I've been self hosting my mail using the magic of MIAB(https://mailinabox.email/) for quite some time now. I do like it, it's very easy to use and has caused me very few issues.
Setup was very simple, I just ran curl -s https://mailinabox.email/setup.sh | sudo bash then followed the instructions, then using the web portal I setup my account and in under an hour I was good to go.
I have run into issues where I've been going into people's spam, but that seems to slowly be getting better. I occasionally have to tell people to look in their spam as well for emails, but I'm sure that mail servers on the other end have started to put a better reputation on my sending IPs and mark them as good.
I really do like that MIAB supports IPv6(YES MY MAIL SERVER DOES INCOMING AND OUTGOING VIA IPv6!!!!) and that was very easy to configure too, just point the DNS records and it takes care of the rest. I do occasionally check headers to see what protocol was used, and usually it's been IPv4 sadly, I hope that more and more traffic goes via IPv6 in the near future(I'm rooting for IPv6 on everything).
I did setup remote backup to a rsync.net. I had some issues setting it up, but was caused by me being dumb, and some issues that MIAB has, but it was handled. I should probably create an issue so they can fix it, but don't have logs for it anymore and don't want to recreate the issue anytime soon. By default it backs up to the same box that you are using so if you are running on no RAID some RAID where you don't have parity drives you might lose all your emails, so make sure you are syncing your backups elsewhere.
I did have to learn a bit about the proper DNS records needed for mail servers, but those weren't that hard to make, and MIAB gives you a zonefile for the almost all the records that you just have to add in.
Overall, I think self hosting your mail server is a fun experiment. I 100% don't think it's worth doing for anything professional grade, so all business mail is hosted elsewhere(I picked Microsoft 365 since that's kinda the one most others use), but for personal mail where I can experiment around with, it's a great way for me to learn new skills.