@verified_human_user From the "Zero-Access (or Zero-Knowledge) Encryption" section of your article it says:
>In this case, once the user has finished reading the email, it is re-encrypted before being sent to the provider’s servers for storage.
I am not sure what that is referring to. Normally email encryption uses some sort of "encrypt once" scheme:
* https://articles.59.ca/doku.php?id=pgpfan:encryptonce
The email should never have to be reencrypted.