What is the difference between full end-to-end encryption and end-to-end encryption?
Are there any differences between these two terms?
There is no difference. End-to-end encryption simply means that both endpoints share a secret key which is used to encrypt all traffic between them. There is no difference between "full" end-to-end encryption and end-to-end encryption. It's like the (lack of) difference between forward secrecy and perfect forward secrecy. They're just different terms to explain the exact same concept.