As a fellow college dropout who had the same insecurities and actually went back to college in his thirties (part-time) to study exactly this... all that knowledge still doesn't prepare you for time-boxed stressful leet code interviews.

The people you are competing with study leet code for 3 months and get really good at solving coding puzzles within 45 minutes. Study the basic data structures (nothing fancy needed beyond binary trees) and solve leet code an hour a day for 3 months. That's all you need to do.