Get Dex to the bowl

Dex can't see over the walls — you can. Tap an arrow and he runs until the maze offers him a choice. No wasted steps keeps the full 100.

Dex runs until the maze gives him a choice, so you are not steering him — you are choosing at junctions. That makes the game about reading ahead rather than reacting, and the full hundred points goes to a route with no wasted steps at all. Look for the corridor that doubles back, because it is almost always the one that costs you the perfect score.