This was very true for me, switching jobs after six years where I had become a domain expert. There is definitely a psychological aspect that makes it difficult

This was very true for me, switching jobs after six years where I had become a domain expert. There is definitely a psychological aspect that makes it difficult—you feel awkward being the noob when you're used to being the expert. There is also just a plain skills gap—you apply your skills differently as an expert than a noob and so you will need to relearn to operate in that new context. When switching jobs, I looked for something that was different, but not so different that I would be overwhelmed. I was still a bit overwhelmed. I think it took me almost two years to reach my "comfort zone" again. It was worth it though. I built up a lot of new ways of thinking about things that I never would have had I stayed with my original job.