A communication between two communication partners, which on a technical level can also be called „endpoints“ or „ends“ of a connection (or more general, of a channel of communication), is either encrypted, or it is not. If somewhere in between the „ends“ of the connection, encryption takes place, such that there exist parts of the entire communication channel which are not affected by it, then the comunication itself is not encrypted.
There is no debate about „end-to-end encryption – yes or no“ but only about „encryption – yes or no“, and the answer to that question must clearly be „yes“. Any service of communication that claims to offer encryption, except that this encryption „is not end-to-end“, does not offer encryption at all.
This is a surprisingly simple resolution of an apparently difficult question.