Tolkien said that his works didn't intentionally contain any specific allegories. In other words, Gandalf is not supposed to be a direct stand-in for Christ for example. But that doesn't mean that there aren't Christian influences on Gandalf that the reader can infer, along with other types of influences, or read into Gandalf futural aspects that didn't even exist at the time of writing. There is complexity to Gandalf.

He just didn't like simplistic meaning like that because it kills the depth and layers of interpretation to the story. Instead of saying "Gandalf is a fully fleshed out, independent character" people say "Gandalf is just Christ!" and either leave out or don't need or want the Gandalf character development because they already know he's just Christ.

I use that example specifically because he disliked how C.S. Lewis (close friend of Tolkien, by the way) made the Lion in Chronicles of Narnia a literal and direct allegory for Christ, like the Lion is literally Christ, which Tolkien found to be lazy and hated allegories for this reason.