I have been running my own mail services continuously since about 2006. I have, over the years, gone through a number of Linux-based mail systems from base tools, to zimbra, to mail-in-a-box, to mailcow. While I would like to say that I configured each of them perfectly, I was only 14 when I set it up and SPF/DKIM/DMARC records were not a thing yet. Sorry for the spam I inadvertently sent back then!
Currently I run Mailcow to provide e-mail services. This is hosted on a VPS with a clean IP that stays off of spam lists.
Running a mail server in 2026 has a bit of an infamous reputation for being difficult to maintain and consistently have mail delivered. While this is more difficult than it has been in the past, it's still possible without too much trouble. I use DMARC/DKIM/SPF records and that, combined with a proper grade of IP, allows mail delivery to the major providers without issue.
Mailcow also provides CardDAV and CalDAV sync to sync phone contacts and a personal calendar. This is part of my Google services replacement.