Your confusion is around where the end is in this case. E2E would be encryption from the ring device to your other device being used to view the feed (your cellphone for instance). Part of the difficulty in that case is getting the encryption key securely transferred between the two devices without exposing it to anyone else (a non-trivial problem). Assuming that was done in this case Ring employees would only have access to the encrypted videos with no access to the decryption keys to actually view them.

E2E Encryption is usually referenced in messaging applications where the ends are understood to be the two communicating parties, while in this scenario it's a little more nebulous.

In short, yes, because end-to-end implies only a single producer and consumer have access to the data. Storage in the cloud wouldn't be an "end", and therefore it must be encrypted at that stage. The ends are 1) where the data is created by the device, and 2) wherever it is viewed on retrieval by the end user. While it's in the cloud it's still "in transit".

Facebook, if I recall correctly, at one point seemed to be trying to redefine the term to be "encrypted on its way to us and then back out again", which IMO is nothing short of propagandizing to confuse people, I assume to foil demand for real E2E encrypted products and gain unearned trust.

At least in Apple's case, they do not have the keys because it is encrypted by your devices and then uploaded. It is then only able to be read by your devices because they have the keys to un-encrypt it.

The latest Apple platform security doc (fall 2019, available as pdf) does a half-decent job of explaining their key distribution mechanisms (iCloud Keychain, they call it) too. They are doing some pretty complicated stuff under the hood to support multiple devices (trust circles, they call it).

I just wish I could read the source code to make sure theory and practice are reasonably congruent.