Gotcha. It could be entirely possible that the anecdotal experiences regarding phone data that you've heard could be simply because they're heavier users or that they purchased a smaller quota. From personal experience, I really have not noticed any background processes that suck up data.

Regarding the type-C cable though, I have actually experienced that problem where cheaper cables do not work for charging. This part is PURE SPECULATION on my end, but I suspect Apple stops cheaper cables from charging on the off chance that it increase the risk of a fire (cheap cables = thinner wires = more resistance = more heat) because when stuff like that makes the news, the headline is typically "iPhone caught fire while charging" and not "Cheap cable caused a fire." I spent a lil more on a third party USB-C cable that was higher quality and rated to charge up to 65W and have had no problems with it. I'm not sure what the economic situation is in Latin America, but where I am (Malaysia), I spent about RM60 (which is roughly equivalent to $13) on the cable that worked compared to RM20 for the cable that didn't, just to give you a point of reference.