I mean, as you point out though the “theology of sin” is really just a reference to consciousness and the ability to chose the non-optimal courses of actions (as opposed to angel or AI who can only act according to pre-ordained instructions).
I think most likely God is running an experiment with humans, to see whether we would love him if we had to choice not to (as opposed to angels who simply have to). The point of Jesus’s sacrifice is to remove the focus away from the behavior and towards belief. Most humans are just not capable on executing on their own desires anyway, just look at the struggles we have trying to lose weight, so God just told us through Jesus “hey don’t worry about actually pulling off angel-like behavior, you just have to stop being selfish and believe in a higher power AND each other (as per Jesus’s highest commandment)”.
So yea, believing in Jesus is not as easy as believing that all of existence is an illusion, but it’s precisely because it fundamentally changes how you look at the world that it ends up so transformative.
BTW Live and let live of course. I’m not here trying to impede on your journey. I just want you to see that there is another answer to the questions you pose. Tons of Christians wonder about the same things, but we know from the get go that we are not gonna get all the answers (just look at the concept of the Trinity…), yet we just approach it with wonder and curiosity.