Yeah Tutanota is pretty simple and easy to use and is a basic e-mail service and works like one. It works perfectly fine for the purpose of just e-mail. Never used Protonmail but I'm told it has more features with plans on adding moar in the future.
Protonmail and Tutanota are probably the most popular ones due to their end to end encryption and advocacy for privacy in general. The former is Switzerland based and the latter based in Germany.
https://www.zdnet.com/article/yandex-said-it-caught-an-employee-selling-access-to-users-inboxes/
If your looking for alt tech, maybe Yandex shouldn't be your Gmail alternative. :p (y)