That's one of my major takeaways from BJJ after over a decade: competition separates what you know and what you think you know. What you actually know and what you'll actually do is a really short and simple list compared to the multitudes of knowledge and trivia you'll see and collect like trading cards. I was practicing going from ashi garami to a heel hook for a year before going to a competition that allowed it and the moment I saw an opening for it I messed it up bigly and let a person I was frankly more athletic than win.