I was honestly never as drawn by CS Lewis’s works; neither the more adult and children’s fiction. Tolkien was more my speed. I found Tolkien’s attempt to give England a mythology, not to mention what I view as a stunning merging of a pre-Christian pagan Nordic tradition (the Valar stem in part from the Germanic pantheon) with a fundamentally Catholic notion of Godhood.
Yes, the Valar are gods, in that they are supernatural beings of great power who predate the world, but they are not God. For the most part Tolkien masters this by keeping Illuvatar out of the narrative, save for the Ainulindale (the Music of the Ainur), and at a few critical points, as when the Valar hand over the governorship of the world to Illuvatar when the Numenoreans rebel and set foot on Aman (the undying lands, the home of the Valar). Thus he evades treading, as it were, on any Biblical territory. The Bible doesn’t say how the Earth was made, and certainly leaves room open for the notion that some angelic beings might be involved in the governing of things on Earth, so that these are not heretical views.
There are only two things in the entire mythos that I’d regard as “one to one mappings”. The first is Melkor, who is clearly Satan. While you don’t even get the full sense of Melkor’s native power even in the Silmarillion, in the later released writings, in particular Morgoth’s Ring, we get some very good detail on how Melkor became Morgoth, that Morgoth was a shadow of the original Ainu Melkor, who was the mightiest of all the angelic beings, and who dispersed his native powers throughout the Earth to control it. Thus we have a shadow of the Judeao-Christian Fall, that the world was fundamentally altered and made less than it was at Creation, and that it is now stained.
In Morgoth’s Ring is well is a surprising bit of narrative where there is some suggestion that mortal men (as opposed to Elves) were turned from God by Morgoth. It is fashioned in the form of a legend that the men who first enter the narrative of the Silmarillion tell the Elves that a being appeared among them, and turned them to sin, and that sounds a LOT like the Garden of Eden story. Even Christopher Tolkien expressed some surprise at this, as this sort of direct allegorical correlation was so unlike his father.
But other than that, I think LotR and the Silmarillion are Catholic works in a more tenuous respect, and he never intended you to identify Gandalf with Christ, seeing as Illuvatar is God, and, though never actually dealt with within the mythos (which in Tolkien’s view, would have been pre-Christian, even pre-Hebraic), would certainly have been the Father, the Son and the Holy Spirit. Gandalf was an angel who was slain by a demon (and by slain, rendered impotent and would have taken a very long time to recover, if ever), and was resurrected by Illuvatar. That might be seen as presaging Christ’s resurrection, and is Christ-like to be sure (but then again, some point out the Christ-like symbolism in Superman as well).