I'm Buddhist, and it's always struck me as odd that so many religious people require their text to be literally true.
If it were to be definitively proven that the person called Jesus Christ never existed as a historical person on earth, the various Christian churches and organizations would stop at nothing to attempt to discredit this. They would be furious.
On the other hand, if it were definitively proven that Siddartha Gautama, the person who will be called the Buddha, never existed as a historical person on earth, most Buddhists would find it interesting, probably even humorous, and would go on happily practicing Buddhism.
Because it's not about the person, it's about the Dharma, the teachings. Those exist with or without a historical Buddha, and that's what guides the practice.
Imagine that someone is showing you the moon by pointing at it. You want to look at the moon, not the finger. The Buddha is a finger pointing at the moon.