Special Interests Are Not Intrinsically Idolatrous
While we autistic people tend to focus on our restricted interests for long periods of time, that doesn't necessarily mean we're committing idolatry.
For example, I love to write stories. It's one of my restricted interests. But writing stories is not my idol.
My stories are the work of my mind and hands so they're not my Creator. They are my creations. They're my kids in a way.
They can't save me, either. The mere idea of me expecting my own creations to save me is absurd.
Writing stories is how I express myself. It's how I cope with the deaths of characters I love. My stories are often "what if" stories.
In fact, when I'm writing stories, I'm glorifying God. When we create good things, we glorify God. The act of creating something good glorifies God because he is the Creator and we are made in His image and likeness.
Also, I found a priest named Father Roderick. He uses pop culture to evangelize. So my fandoms are helping me understand God better through Father Roderick.