I have been mulling over Posteo for encrypted mail. Looks like a lot of the same benefits as mailbox.org, but my main attraction was the price (one euro per month) and fact that they do not associate payment with your email account. Haven’t done a deep dive but will compare to mailbox.org before I pull the trigger.
What legal jurisdiction do they operate in? I see German and English versions of their site but nothing in About Us on jurisdiction.