If you have any reasonable skills as a programmer (which I have to assume if you have been programming professionally for some time) then you should stop watching videos, etc. As you have observed many are poor quality and aimed at beginners. Many so called challenges are created by jerks who are trying to prove that they are "clever".

Why don't you pick up a well recognised book and learn from that instead. I'm thinking along the lines of SICP (Structure and Interpretation of Computer Programs)? Yes, learning a new programming language probably would also help with your progression.