The base — matters most
Adherence
This is the whole thing. Not the sexy part, but the part that decides whether you ever get lean. A plan you can actually stick to beats a "perfect" plan you quit in two weeks — every single time.
It has to be sustainable, and it has to be built around your life — your schedule, your food, your preferences. If it isn't tailored to you, you won't hold it, and if you don't hold it, nothing else on this pyramid matters.
Yes — a calorie deficit is what physically burns fat. But a deficit you can't maintain does nothing. One week of dieting changes nothing. I'd rather you run a tiny deficit you keep for months than a brutal one you quit in a week. Consistency is the multiplier on everything else.