You don't have to have all the cards to compete in netrunner. there are only a handful of really essential pieces or silverbullets that you need to have/know or counter
Everything about netrunner is piloting and knowing your deck and your opponent's
because of the assymetrical gameplay you need to know both how to know your deck and how to play it against the diverse strategies, if you dont have a counter play to a strategy you try to think what your deck can pull off ,add a card for the match up OR accept that you will lose most of those games
i have a very small collection, but i can compete in my local game store pretty good (1st or 2nd place) and on jinteki net (using only cards i own) both in casual rooms and competitive
tl;dr Stick with 2 decks, and get to know them REALLY well. then start getting to know your match ups and what you need to do vs them.
changing decks all the time or playing decks without knowing how to play them or their match ups is a recipe for failure
ofc you will keep changing your decklist until you find something that works vs almost everything ,brewing, changing cards is all the fun in games like this one
unless if you just netdeck..
don't overthink this so much, dont paralyze yourself with information, the best way of learning is is playing and practice (reading articles isnt bad, but for a total newbie playing is vital, leave theory out see it live,THEN you can start delving deeper n deeper)
that's what you need to know about netrunner