What threat model is it that a email vendor can receive your email in essentially plain text (TLS between SMTP servers doesn't protect you from the provider themselves snooping) but cannot be trusted to store that same email in situ?

Hard to recommend something without understanding the thought process.

I used to be concern over what happens to all the sensitive information I put out on google's servers, I was so concerned that I even started following Richard Stallman's guidelines until I realized how quality of my life decreased and how unhappy I've become for the sake of being secured. You can of course achieve some balance and protect only the most important things to you but don't fall into the trap of overdoing it.

I'm back to using Gmail again.

I understand the sentiment. I certainly have my own bouts of intense paranoia related to security and the privacy of my personal stuff. It can become unhealthy. However, I think as long as the majority are complicit with email providers that don't offer end-to-end encryption, we may fall deeper into the clutches of government surveillance, targeted advertising, and other practices that IMO are an overall toxic influence on humanity. I don't practice what I preach at the moment but hopefully the loss of convenience is not too significant as I make the switch.

posteo.de is great. Here's a good chart [1] comparing various providers with respect to privacy and other important factors. In my case, I went with Posteo because they offer the nice combination of anonymous payment method, located in Germany (so not as bad for my metadata as, say, five-eyes countries), and offering POP3/IMAP, so you can use your own client and have a local copy of my mail without any weird bridge software.

[1] https://thatoneprivacysite.net/email-comparison-chart/

Don't allow your own domain, which should disqualify them. Especially since nobody knows whether they'll survive the next years.

Having a GMX address, fine. I wouldn't want it, but I'd expect them to be around in ten years. Posteo, who knows?

I use @icloud.com email address. Just make a new Apple ID and it comes with free icloud email address. It pairs well with Mail on macOS as well as Outlook. I trust Apple way more than Google or any company that is in the advertisement business for that matter.

Fastmail; cheap, fast, reliable, and I can use my own domain. If you want end-to-end encryption, ProtonMail is an alternative.

mailbox.org has been great. They can encrypt all your incoming mail content with your PGP public key. And you can enforce to receive the mail over a TLS encrypted SMTP using a special subdomain.

I use ProtonMail with a custom domain.

Gmail I believe is technically encrypted at rest, just they also happen to have the keys.

I use tutanota.com

Outlook.

try superhuman.com