Another upvote or seven for fastmail.com - I spent a little too much time spinning my personal domain hosting through Fastmail, Tutanota, Proton, mailbox.org… and then came back full circle to Fastmail.

Their shortcomings, if you’re concerned about privacy, are listed right above^^^ but I don’t think you can find a better email hosting provider for the pricing.

So what method do you use to backup everything?

Depends on what OS that server is running. Windows, Unraid, Linux, NAS (like Synology or QNAP), etc.

There are a bazillion different ways to back up your data but it almost always starts with “how is your data being hosted/served?”