“How much is enough?” Is an interesting question for legs. I used to do legs twice a week - 3x5 heavy barbell squats, then 5x10 heavy leg press, then leg curls and extensions, then calf raises. I was able to add a lot of weight (especially with leg press machine). I’d be sore AF, but it did nothing for my athleticism. Now I do 3x8 Bulgarian split squats every time I lift and I don’t feel like I’m missing anything, plus my knees are more stable and strength is more balanced.