I admire your courage in posting this. I've felt this for years with my career in IT security. I work with and meet a lot of smart folks in my field. So I always feel like the dumbest guy in the room. But I try to remind myself of the years of self study and grind that I put in to get where I am. I guess that impostor syndrome can be a healthy fear if it keeps you striving for improvement, regardless of what anyone else thinks. Just one opinion here, but i think you're doing good, well intentioned work.