Sensucht94 I haven't had issues with any of that. Learning how to do it was the hardest but, once learned, it's all relatively easy and the only annoyance is monitoring it--checking the logs--and the occasional adjustment. Less than a couple of minutes as I wake up in the morning and drink my coffee. The server I still have at home is silent and only consumes as much as a 40-Watt light bulb. The company servers are a little more involved but they have a lot more traffic, too, and it's all part of the overall maintenance with that.
I used to have a Rpi3 running my mail server on NetBSD (opensmtpd, dovecot, rspamd, dkimproxy, squirremail, squid, NPF, blacklistd). Myself, I was the only client to rely on it,so could afford having an embedded device taking care of my Inbox: no power consumption, no noise. I maintained it remotely and everything was running fine. Then I made the mistake of switching to Void Linux and it broke 3 times. Once someone modified Postfix template and removed UTF-8 support, had to revert it; then it was the time of libressl update and it broke something else I don't remember; last but not least a kernel
update made system
unbootable.
A couple of months after I got my domain revoked as somehow I had forgot to check automatic contract renewal.
I'm not saying running your own mail server isn't good practice, it's fun, productive, secure, privacy-keeping, cost-effective compared to paid professional providers (e.g. fastmail, which I use now), a good learning experience.
But you need patience, care, attention and knowledge to do that, and I not always have (I assume all the fault for this)