Databases, programming languages, compilers, operating system internals, networks these things are pretty complicated in itself. With your day jobs you can't master any of this without spending years in your part time. But now at least you can start something of your interest and learn on the way. Learning a new concepts, implements it, test it and reproduce cycle is so fast that it is only possible because of AI. You need to find the process which works for you. AI already knows every programming language, its best practices, entire computer science knowledge is already mastered by current state of AI. There isn't any single database internals which Ai doesnt know. If you dont believe just start implementing JavaScript or C compiler yourself without even having knowledge of compilers and in a few weeks you will where you stand. You will not only having a functional compiler but you will know the internals of compiler constructions, all the concepts.