I dismiss the idea that ‘Jesus was Satan’ as nonsense because ‘satan’ was only a generic concept of ‘an opposer’ in Judaism and ‘the devil’ is a fictional character introduced into Judaism and Christianity from the Persians.
As for your simplistic belief that the gospels aren’t anonymous, you’re at odds with mainstream scholarship (including Christian scholarship) so i don’t care. Authorship of ‘John’ wasn’t attributed to him until the late 2nd century.