Taking the question as asked, rather than the general version of it. ApoB is the more informative number and it is cheap. LDL-C estimates cholesterol mass in atherogenic particles; ApoB counts the particles, and it is particle count that tracks risk — which is why the two can disagree and why the disagreement is the clinically interesting case. Triglycerides fall substantially with weight loss and improved insulin sensitivity, HDL moves modestly, and LDL-C often barely moves at all, which surprises people who expected everything to improve together.
Happy to go further on any of that.