Re: skills - my standard advice is, every engineer should learn Next.js and launch a personal project using it. That builds familiarity with some modern tools.
Re: career development - just make sure you have a plan for where you're trying to go long term. Going back to being a contributor is fine if that's what you want, but don't sell yourself short as a leader.
I'm a mid-level engineering manager in a Fortune 1000 company, I spend about half my time doing "manager stuff" (mentoring, leading meetings, high level architecting) and half my time coding (mostly behind-the-scenes platform stuff like tooling, devops, testing). I was unfamiliar with much of our tech stack when I started, but started making small improvements where I saw they were needed, and slowly have been making my way thru the app and learning more.
hope this helps!