[voidmain0001]

Is there a OneNote, Evernote, <insert program/app name> that has the same feature set as ProtonMail? I like the idea of centralized cloud storage of notes for synchronization across devices with the same app/program, but with at rest encryption of the stored content that can only be decrypted on the client with the client's key.

[erredois]

There is standard notes that has the encryption and cloud sync. You can try it standardnotes.org