Is there a 'complete' email solution provider/software?

There are some email features that theoretically should exist, notably encryption, that are just not fully implemented and/or correctly implemented by many of the popular options.

So this made me wonder whether such a 'complete' email solution even exists.

I put 'complete' in quotes to allow for some leeway.

e.g. Even if it has bugs that temporarily interferes with some functionality, as long as there's some sort of on-the-record guarantee or compensation when those bugs affect the user, then that would be good enough for nearly all possible users in my view.