A remembered opening cannot decide what the unfamiliar middle requires.

Knowing how something starts is a genuine advantage that runs out. Memorised openings carry you to the point where the position stops matching anything you have seen, and from there the memory is silent and the thinking has to begin. Preparation is a head start, not a substitute for the part that is actually difficult.

Notice where your own prepared material ends. In the next conversation, game or piece of work, mark the moment you leave the script, and slow down rather than speeding up. That is the place where the useful learning is kept.