Being based in an “eyes” country really doesn’t mean much these days. Those countries still generally have fairly decent judicial systems, so unless you’re doing something which is going to result in a court issuing a warrant, there is nothing to worry about.
There is a reason why the site doesn’t mention “eyes” anymore, and that is because it implies that other countries not a part of that agreement are better, which there are dozens of examples where that simply isn’t the case. It is a very 2013 way of thinking that isn’t all that relevant anymore.
Also regarding Tutanota, the client is still open source and is E2EE on the device.