Ring, by default, already encrypted videos as they are uploaded and stored on Ring servers. Adding E2EE, however, should ensure that only the Ring owner can access and view videos because the necessary key to decrypt the data is stored on a device attached to the account.
With End-to-End Encryption, customer videos are further secured with an additional lock, which can only be unlocked by a key that is stored on the customer's enrolled mobile device, designed so that only the customer can decrypt and view recordings on their enrolled device.
Problem is, because my wife is a shared user, this means that we automatically cannot use the E2EE. That alone is pretty odd as messenger apps can have encryption for a messaging group, and if my wife entered the same encryption key password, it could create the identical decryption for her. It just suggests strongly to me that Amazon made very little effort here to make this workable, and is effectively discouraging the enablement of E2EE.
See Amazon adds E2EE to Ring battery-powered devices
Whether this works as advertised is key