you are correct in being wary of self-hosting email, i cannot recommend it. a lot can go wrong. besides downtime (already pretty bad by itself) i have known cases of domains and/or server IPs being blacklisted/spamlisted on multiple big mailservers (microsoft, google) because of bad administration, effectively killing the self-hosted setup.

you would definitely want a static IP (as opposed to updating DNS entries all the time), a solid spam setup, and multiple failsafes, meaning not just data backup, but also mechanisms for preventing downtime like secondary machines. it really is only worth it if multiple people make use of it and you have multiple dedicated admins, in my opinion. but in that case, i think it can be very cool.

as others have pointed out, a good (and in some sense the canonical) option is to use something like mailbox.org with your own domain, or other providers, or even a webhosting package from netcup or hetzner or similar. these are all solid, and you have professional support.

side note: downside is, your data there is more snoopable, less so with something like proton. but that shouldn’t be your biggest worry, since emails always exist not just on your server, but also on the other side of the communication, and you have no guatantees for privacy there. e2ee (like pgp) is what you would need in that case.