I tell non techy people to use a physical book that they can secure. People know how to do hide things or put them in a safe. Digital security is harder to understand and I would say a book in a safe place is way better than reusing passwords they find hard to remember.
If you don’t mind having email go through Gmail etc, then you might not want to full host, but just run a local IMAP server. There are some pop to SMTP solutions you can use to pull your emails (fetchmail.) you can then use your account as an outbound relay. Keep in mind you’ll only be able to set this up for a single account if you use something like Gmail.
If you buy a business product like workspace or m365, you should be able to setup relay/hybrid connectors for multiple accounts.