On the topic of Custom Email
So, I have been working on trying to setup a backup personal email on this domain. I want to be able to move between services, etc, etc. Thus far, I've narrowed it down to these three:
Protonmail
Its good, secure, relatively cheap. But they don't support real IMAP or JMAP, you have to use their app, and that feels strange. This said, those apps are AWESOME.
Fastmail
Which is kinda the opposite of Proton in that is all about custom support, standards complaint, and pushing forward what email means. Its also been around for over 20 years. You want an email service which will last.
Mailfence
Another privacy focused mail org, this one recommend by the folks over at mozzilla. Downsides are that they don't seem as focused on the technology side of the business.