I am a self-taught programmer and I do not have imposter syndrome. I have a degree in electrical engineering and when I thought that was going to be my career I did have imposter syndrome, so I’m not immune. I wonder if there’s a correlation. It seems that many if not most professionals suffer from imposter syndrome; I wonder if that’s related to the way they learned.
When I say self-taught, I don’t mean I never took a class, I mean the majority of my programming skill was learned by doing/outside of classes. I took a Java class in high school that helped me graduate from procedural languages to OOP, and I took classes in college but with few exceptions the ones that were practical (vs theoretical) covered material I already knew.
I’m self taught and have pretty bad imposter syndrome. Don’t think that’s the magic bullet.