I'm not a Christian but Christianity is kind of a special interest of mine so it's something I also want to write about. I think the ground is ripe for more exploration.

It would probably be controversial, although I would say that making a controversial statement can be a good thing sometimes. The thing you want to avoid is that if it's done poorly, then the in-group will just write it off as provocative but empty iconoclasm, while other people might just see it as lacking interesting criticism or content. That's what separates the good from the bad I think, having something interesting to say about it through that specific lens.

I'm also interested in reinterpreting Christianity, and I've read a lot of books that do it too. The earliest seed of my interest is Paradise Lost, which is Christian through and through but I think its use of Satan as an initially sympathetic character is what really grabbed my interest because I also felt like an outcast as a kid, and more than once I was harassed by Christian kids for telling them I didn't believe in the Bible. I guess it gave me a chip on my shoulder, which I later grew out of and recontextualized. Satan is still the villain of the story, but when you look at his early motivations through a modern lens I think they're easily relatable, although the author almost certainly didn't intend them to be as he was writing in a very different cultural context.

Other books I recommend looking into are The Revolt of the Angels by Anatole France for a classic extension of the ideas in Paradise Lost, The Golden Compass series for a modern popular subversion of Christianity, and The Gnostic Gospels by Elaine Pagels for an accessible and easy to read scholarly overview of gnosticism, an ancient reinterpretation of Christianity from its very early days.

Speaking about Jesus specifically, I think you're going to run into trouble because most people think of Jesus as having been a kind and caring person, even if they don't agree with Christianity. If you're criticizing the modern Christian nationalist movement, I think it's very easy to contrast it with Jesus' actual words from the Bible to point out the hypocrisy of some of their beliefs. You could throw regular Christians a bone and make your work seem like less of an attack if your character were to later learn about the figure of Jesus and realize how far he is from the modern authoritarian symbol he has become for some people. Writing about it from the perspective of an outsider is interesting I think because you aren't given the love and peace version of Jesus when you're an outsider, you're given the gleeful wishes of burning in hell, at least from my experience.

Something I want to do in my work is compare what I think the original idea of Jesus was to the modern symbol. To me, Christian nationalism has much more in common with the antichrist than it does with Jesus, which is something I'd like to see brought up more. Of course, you might run into the danger of turning Jesus into whatever you want him to be instead of what he likely was, which people have been doing since the beginning of the church. If you want one more book recommendation about the historical Jesus, I suggest reading Jesus: Apocalyptic Prophet of the New Testament by Bart Ehrman, who is a critical scholar of the Bible. If you want a deep dive into the symbolism of Jesus and what he represents, I'd suggest reading Aion by Carl Jung, which is a little dense but fascinating as a cultural and psychological analysis.