I've heard that Napoleon wasn't a great military leader and that his generals did a lot of the leading for him.
You've heard wrong tbh
Austerlitz alone was a stroke of pure military genius. He was also what I would describe as a "complete commander" - by which I mean not only was he a master of battlefield tactics, but a masterful strategist/campaigner and an inspirational leader as well. Always maneuvering into advantageous positions, dividing allied opponents attempting to join forces and routing them each in detail, encircling entire armies (case in point being the Ulm Campaign), etc.
He became almost lazy as he got older and started using more direct tactics (arguably losing some of his genius) but even in the Hundred Days days campaign he frustrated Wellington with his movements ("Napoleon has humbugged me, by God; he has gained twenty-four hours' march on me").