When you reach 2100, I think you need to know 20 moves of some openings.
Do you? Jeeze... no wonder I'm still three points short.
To the OP: Studying opening lines even eight moves deep is a waste of time at your level. Study tactics, tactics, tactics, model mates, endgames, pawn structures, and the typical middle-game plans that arise from them. Play lots of slow games. Analyze your own games, especially the losses. Post some of them on the forum and ask better players to criticize them. Develop a thick skin so that you are not offended or discouraged by harsh criticism. And play. Play, play, play.