Pfizer is still fighting and settling lawsuits claiming Lipitor causes type II diabetes. Space Dr. Duane Graveline took Lipitor and claimed it causes memory loss. Let buyers beware.
https://www.classaction.com/lipitor/settlement/
https://spacedoc.com/articles/graveline-statin-side-effects
https://advancedq10.com/dr-duane-gravelines-video-on-cholesterol-q10-and-statins/
You mean that high cholesterol can be a sign of magnesium deficiency? My understanding is that plaque is essentially a scab over a damaged part of the artery and the scab is made of cholesterol. High cholesterol can be a sign that your arteries are damaged.
Magnesium is an essential nutrient. So many body functions rely on magnesium, and as you said, if you are low on magnesium, you won't absorb calcium. You also won't make Vitamin D, either, and Vitamin D production is one of the ways that cholesterol is used up by the body. So I guess the lack of Vitamin D production can be a sign of low magnesium, too.
What is interesting is that most Americans are magnesium deficient, but the AMA doesn't recommend that people take a magnesium supplement. They do, however, recommend that women take a calcium supplement, which exacerbates the magnesium/calcium imbalance that already exists in the typical American diet.