I want to add that there will be a number of security/privacy conscious users that will not be willing to use the sync features (iCloud) without End-to-End encryption. I understand when you say that you are scared of the forgotten passwords but that should be for the individual to decide. If there is a password recovery mechanism then what’s the point of having information encrypted. End-to-end encryption is becoming more and more familiar to users and they understand when you give them a warning that losing the password will lock them out forever. Users will only trust your encryption if they know you do not have a backdoor to recover their password.
Two of the apps that I use regularly, that use end to end encryption are DayOne and Standard Notes.
DayOne allows end to end encryption journals but it warns you that you will lose some features if you use them (no web editing for example). That is understandable and and a compromise that many users will be willing to make for the sake of privacy.
Standard Notes allows encryption across all notes and does allow rudimentary search as well. You can even look into how the encryption works for it since it is an open source project.
I am glad that end to end encryption is in your road map and will be looking forward to when it is implemented. Unfortunately, I will not be able to use it for much until that feature is added. And of course, it can certainly be a premium/upgrade feature.