2 of everything would still be too unreliable to pass all the checks. In a blind playthrough where you want to pass as many checks as possible that's a fair idea but it is very likely to end up as a failed run, but once you know what checks you will get in the different events there's no reason why you shouldn't adjust your deck on the fly (e.g, if you already did all the events that use white cards, no reason to keep them on your deck, replace them with whatever color will be used in the next check).
Think of it as a rotating deck, switch out what you know you won't use next and switch in what you know you will need to increase your odds.
Also some routes require extreme dedication to passing certain checks with whoever is your tutor, the ones that don't use the corruption system mean you should always keep some of the required cards in your deck, regardless of councillor events. Also some routes only unlock after failed card checks, so you might want to get rid of all the cards for that check, etc.
