I’m aware of what end-to-end encrypted means in a technical sense, but does the lack thereof guarantee the messages are just plaintext readable to whoever’s manning the machine?
My guess is yes but I’ve been known to have wildly incorrect guesses so I want to double-check.
It would mean the server owner can almost certainly read everything. Though it may not be in plain text. It could be encrypted on the server. But the owner would need to have the keys to decrypt and read everything so it all works.