Yep. But when I say, "Jesus could be a myth" it's in the same way that I say, "Hercules could be a myth"
Both could be a myth, but there's a decent chance both Jesus and Hercules actually existed. There is levels of mythology though. There's a small chance neither existed. There's a much larger chance that both existed but neither were Gods or demi-Gods. It's more likely that both existed, both convinced people that they were Gods, but neither actually had the power of Gods.
I know Christians often like to say, "Do you really think that a regular human could fool all these people?", and to that I reply, "yes. Because I we see it so often". So many cults have formed with devout worshippers convinced that their leader is a holy being, beyong human. What makes their divinity less true than that of Jesus, or any other religious figure?