Does anyone recommend any alternate providers with custom domains, or some OSS? Is it possible to host your own email server on a NAS or RPi something?
More recently though I moved my personal domain to Microsoft Exchange Online - it's a lot less flexible than Mailcow (per-head licensing, but there's + addressing and catch-alls now) but I don't have any of the deliverability/gmail-spam-folder issues I used to have.
Exchange P1 Online [2] is roughly the same for my single-user as my old DO droplet cost per month
(edit: side-bonus you get an Azure AD tenant for your domain which is handy for SSO/IdP things)
[2]: https://www.microsoft.com/en-au/microsoft-365/exchange/compa...