Recently in my career I’ve been leading more and larger projects, and a lot of the skills I think more junior devs prioritize, I’ve found myself without. As you move into L4+ roles, I find the more important skills will come from team management, how to decompose problems, and delegate those components correctly given the talents of your other engineers. Critical thinking is important at every step of your career, but probably too broad to say it’s the most important. I feel the very senior engineers at my company are solving broad, architectural and operational issues rather than the individualized or hyper specific issues of the more junior devs. That’s not to say one set of problems is easier or harder than the other, but the senior devs need more “political” or managerial skills, for lack of a better term.