I did a 5 year degree in CS. What remains is not so much the course content but the faint knowledge of how things kind of work. This gives me a very wide scope

I did a 5 year degree in CS. What remains is not so much the course content but the faint knowledge of how things kind of work. This gives me a very wide scope when working on any problem and to provides a better grip when facing new domains. You can't replace the full scope of CS studies with online courses or books simply. What you can do is to start widening your current domain of knowledge. You are a programmer: How does your language of choice work internally? How do compilers/interpreters do it for other languages? How does a single core handle your program? What happens with multiple cores? And so on... You'll find yourself knowing more and more about SO, architecture, etc and you'll be able to take advantage of the knowledge right away (because it's related to what you do) and in the future (because many CS domains share common parts). Last, if books work for you, use them. If hacking some electronics does it, then pursue that. Just find a way to learn things that doesn't get you tired. And whenever you're in the office and someone just talks about something you have no clue, ask for tips, always!