Have an understanding that competent developers, don’t work solo, they have an ecosystem consisting of teams. You’d rather code a process in vanilla that you understand than copying and pasting some library code in the app but you can’t answer why, what, when and how. Efficient software is developed by patient and efficient coders.
Since most processes in JS are asynchronous it’s the not the same in JAVA and C++ perhaps giving you a big opportunity to understand both entirely.
Last but not least, relevancy is subjective though the more efficient solutions you put out in production is relative to the large number of human problems you are helping to solve but you can’t achieve that if you don’t learn and practice breaking down complex tasks into simple modules on paper before getting your hands dirty.