I don't feel confident about my place in research. I am objectively less equipped for this career. How to move forward after a PhD?
While I'm not convinced it isn't just imposter syndrome, I'll also assume that you know something about it already.
However, you sound as if you know how to get the job done in research, focusing on what is needed to perform well. It isn't necessary, of course, to know everything before you start a project. Little would get done if that were true.
However, note that the situation has changed. In grad school and maybe in the post doc you were surrounded by a support system of people that you could bounce ideas off of and get feedback. The more independent you become the less automatic that is. So, I suggest that you try to reproduce that environment virtually by forming (or joining) a circle of collaboration.
A lot of very productive people maintain relationships with their former advisors and become part of that person's network. They invite others to come and speak or they go elsewhere to speak (and meet and collaborate).
It is very difficult for most people to do serious research in a vacuum. A few can manage it, but the collaborative network is a much richer environment for the generation and testing of ideas.
It doesn't have to be a classroom. You can take a much more active role.