I upvoted, it's all good advice, but the blanket statement that "formal CS is useless..." is a little strong. CS undergrad is generalist and mostly about types

I upvoted, it's all good advice, but the blanket statement that "formal CS is useless..." is a little strong. CS undergrad is generalist and mostly about types of problems and surveys of solution flavors and POCs of specific solutions in domains that are hot or cool or whatever and geared to students who are just trying to get through and don't have time or patience to work through bespoke granular details. Getting the idea is good enough for a B. Kernel programming is largely the opposite in all respects. Many topics, problem domains, solution approaches e.g. usually covered in CS undergrad are not relevant for kernel programming. Not useless, but not relevant. Kernel programming relative to most CS undergrad courses is like taking a semester-long lab, but starting from the best A+ project from the last 5 years, and instead of newly solving the problem, spending time working on understanding why the best A+ solution still sucks, under what edge conditions it fails, and then testing how it can be made better.