Bart Ehrman, Robert Funk, Dale Martin, John Dominic Crossan, Mark Goodacre, Gerd Lüdemann, James Dunn, and the list goes on and on.
If books are not your thing, you can find a great Yale course about the subject here: New Testament History and Literature with Dale B. Martin: https://www.youtube.com/playlist?list=PL279CFA55C51E75E0
But you're original claim about the accounts about Jesus copying from Greek mythology, etc.. is just not viable historically.
I encourage you to delve into the literature actually it's quite fascinating! A good book to start with that I've enjoyed is Did Jesus Exist by Bart Ehrman.
I'll look into the sources you mention, though. I haven't gotten deep into the study of religions themselves but I'm sure I'll want to at some point.