If you expect your emails to be inaccessible to anyone except you and the recipient you'll have to encrypt them anyway. If you are worried about the data-mining for ad purposes on other providers switching to a paid provider like Fastmail is still a good option and while everyone is subject to ad-tech data mining not everyone is subject to a targeted collection by a government actor most of the time.
I want to bash Trump's latest haircut without fear of incoming, frivolous litigation.
I do, however, expect consequences if I do something really stupid.
As with gmail the fastmail provider does read your email content to provide e.g. search (and in case of gmail who knows what more?). Both will hand out information with a lawful warrant. -- And as long as the government is reasonably sane [2] that's perfectly fine with me.
[1] https://fastmail.blog/2018/12/21/advocating-for-privacy-aabi... [2] otherwise I'd try ProtonMail (but it has a price in useability)
However a service not randomly shutting down or dropping support for open protocols _is_ part of my requirements for an email host.
They exceed all my expectations, and I‘m picky.
NOTE: it is not as AJAXy as Gmail.
[1] https://news.gandi.net/en/2017/01/introducing-sogo-new-webma...
[2] https://sogo.nu/
Posteo.de (no custom domain support), runbox.com, mailbox.org, mailfence.com, migadu.com, mxroute.com (if you don't mind hosting in the U.S.), ProtonMail (needs a bridge software to use IMAP) and Tutanota (no IMAP support)
If you'd like to support the next generation JMap (which Fastmail develops), then getting a paid subscription on Fastmail could help.
Any suggestion for a comparable email service?