> We don't have true E2EE yet because our service needs access to message content

That means you don't have E2EE, period. Implying that there is such a thing as "true E2EE" (as opposed to "E2EE") either indicates that you don't know what E2EE means, or that you're scammily trying to do what Apple does with iMessage and say that something that isn't E2EE is, for marketing purposes.

E2EE means that nobody except the endpoints has keys. There is no such thing as "true E2EE" any more than there is such a thing as "true pregnancy".