I would get the prenatal caps and skip the collagen caps. The reason why prenatal vitamins often lack in collagen because it’s not typically the ingestion of collagen itself that causes your body to produce collagen… “you are what you eat” is not to be taken literally… though it’s an easy trap to fall into.
Typically you break down pretty much everything you eat into base level amino acids and other rudimentary building blocks, and your body makes what it needs out of those components… even though it might be more efficient if you could eat steak and just let the muscle tissue just go straight to where you need it… but if that was how it worked you might have to eat human way more often than one would like.
Anyway, the point is, think of collagen like a brick wall… if you want your body to make collagen you need to mix mortar with water to initiate chemical reactions in the mortar powder so it will set… and vitamin C, vitamin A, vitamin E, and vitamin B1 (also called thiamine) work together like water in the mortar mix… each has an important role in the production of collagen (the chemical reaction part). Usually prenatals include a couple of essential amino acids lysine and threonine which are sometimes harder to get through food ingestion in large quantities… these and a ton of other things all come together to create collagen in the body.
It really is fascinating because we’re basically a shitload of collagen with some calcium beams holding us all upright. Definitely read about it on wikipedia.