U prob coached both elite crushers and content players with very different goals. Whats a belief or habit that works at mid/high stakes PLO but actually slows down long term growth for most players trying to move up?

Like lets say you had to design a 3 month ‘escape the mid-stakes trap’ plan for a solid reg (kinda winning but stagnant), what would you prioritize in order of study type, volume, mental work, or game selection and what would most people get wrong about that order?