You are confusing tactics and strategy. You're right that if Lelouch was a master strategist, he would do a lot of things differently and get into fewer fights, but it's established early on that his reach usually exceeds his grasp due to his motivations being questionable.
Tactics refers purely to the way in which an engagement is conducted. Lelouch generally pulled off multiple wins against superior forces in semi-plausible ways that didn't involve pulling constantly pulling new Knightmare Frames completely superior to everything else on the field out of his ass.
In contrast, every 00 victory was completely dictated by the power levels of either the mecha or pilots in question. Tactics played no real part in the vast majority of 00 battles, and most fights were ultimately decided based on who was getting a power-up that day or who had the better robot out of the gate.