I mean you basically wrote the whole article in your comment above by saying: "whether the historical Buddha existed at all"
I'm betting he probably did exist, because when you take all the personal anecdotes in the scriptures, many of which are mentioned in the article, they make coherent sense as the life story of a single human being.
The little details and the personal quirks all add up.
But as I understand it the Buddha is mentioned in a lot of completely independent contemporaneous texts whereas Jesus is basically only mentioned only in the Bible. In itself that doesn't prove anything... the Buddha was active as a spiritual leader for many decades, and Jesus only for 3 years, and maybe the wider society around Jesus was just much more interested in political events whereas Indian society as a whole at the time of Buddha was exploring more spiritual and philosophical dimensions. But I've always had the impression that there are proportionally more history scholars who question the existence of Jesus as a single real person than that of the Buddha.