Email service provider recommendations (2020)

I cannot take this list seriously. Let's start with the conflict of interest:

"Personally, I run my own mail servers, but about a year ago I signed up for and evaluated many different service providers available today so that I could make informed recommendations to people."

This is akin to someone saying "I bake my own break and brew my own beer but since people who will never do either ask me my advice, I've tried some breads and beers in order to make some recommendations."

Also, the criteria are almost laughable: "Support for open standards including IMAP and SMTP." I'll grant you that IMAP support isn't universal but is there any service anywhere that calls itself an email provider that does not support SMTP?

Beyond that, disqualifying Protonmail for lack of bringing in your own domain is factually incorrect. I've had a custom domain with Protonmail since 2018 (had multiple domains at one point but moved most of them to Fastmail.com because I don't need THAT much encrypted security).

It really depends on what a person needs. Gmail, while less than ideal from a privacy perspective, is more than adequate for most people. Office 365/Hosted exchange as well as G-Suite are perfectly valid options. As are Fastmail, Protonmail, and dozens of other providers. And if you're adventurous then running your own mail server is always an option too.

There are MANY valid options for answering this question: boiling it down to just two and basing it on information that was factually incorrect at the time is a disservice.