Glad you mentioned K2, which enables moving calcium from soft tissues (arteries, joints, skin) to the bones where it regulates bone remodeling.

I've seen anecdata reported by people who lowered their calcium score by taking K2 (haven't seen any clinical studies). I’m still unclear as to whether it’s serving a protective function (sealing a fat smear from macrophages which otherwise might turn into foam cells, triggering inflammation) or not. It’s certainly an issue once it builds up to the point of stenosis.

That said, most of us don't get enough K2 in our diets. As mammals, we can convert K1 into K2 (different sidechain) but as humans we're pretty terrible at that - and that's assuming we eat enough green leafy stuff to get enough K1. If you look at supplements, there’s some disagreement over which K2 (they differ by length of sidechain) is best. When we convert K1, we make K2 MK4, but you’ll see statements that K2 MK7 is present longer — but that seems to be an effect of how they pack into chylomicrons (little packages that move lipids — fats don’t dissolve in water — from your small intestine) so I’d guess that MK[anything] is good. If you’d prefer to get it from your diet (yeah, me, too) there’s a good list of foods with K2 here — but remember, for animal foods, it’s important that that animal was on pasture (bright green grass is best). Personally, I go the pastured eggs route (duck if I can get ‘em). Egg yolks are a very good source of choline (lecithin / phosphatidyl choline).

There's an interesting story around the discovery of K2. IMO worth a read.