Higher Rated Players

London system is said to have more drawing than winning chances for white. usually that is not ideal for white, but in some situations, it can make sense. for example, in a tournament situation where you are in the prize money already, a win doesnt get you more prizes, but a lose could drop you out of the prize pool...or like in your case, you are playing a higher rated opponent, and you just want to play for elo...you can get a fair amount of elo by drawing against higher rated players...its not the worst plan of "attack".

"I feel openings have become extremely important."
Your feeling is wrong. Openings become extremely important after you become a grandmaster - Kasparov
"I have wondered what to do against higher rated players, > 2000 and how to possible draw them at a consistent basis."
To draw or win against higher rated players, you must play well.
"Do any strong players have any tips for me, and if there are any opening suggestions?"
Just play what you usually play and have experience with. Play the opening slowly and carefully. Take time to think.
"I am going to be playing in the K-12 Nationals this weekend so I need to prepare"
The best preparation for a chess tournament is outdoor physical exercise.

Is it enough to memorize opening sequences 30 moves deep to play well?

I also believe that to run a successful party, you need to work debut. Otherwise, you can get the worst position that is difficult to play. Solid players with a rating of 2200, crush the opponent during the game and begin to do it already with the debut. The task is not to give the opponent a pleasant development of the game and to navigate well in the tactical nuances of the position. For a successful performance in the K-12 tournament need the same actions as against the players with a rating of 2200 lichess.

I suggest to play main lines and to have a broad repertoire. Then they can not outprepare you. Also, if a few GMs are sceptical about an opening i wouldnt choose it. For example, many GMs are sceptical about Kings Gambit, Kings Indian, Dragon Variation, Dutch, etc., but they are not about Najdorf, Berlin endgame, Grünfeld, Slav, etc. I would listen to them. if an opening is rarely played by GMs, dont play it. That said, Dvortzkys hint to develop your own theory is good, it gives you a preparation advantage, but do it within the borders of the main lines.

Further, dont focus on drawing against stronger players, just focus on making good moves. Otherwise you get used to a playing style which wont help you once you got stronger. Those enforce-draw openings also wont help you then. The stronger player is anyway better, so try to get the maximum, not just draws. He will make more mistakes if he needs to defend. Finally, no one is gonna invite boring drawers to his tournaments. People like to observe Kaspy and Morozevich, not Leko and Giri.

#15 "I suggest to play main lines and to have a broad repertoire. "
No on the contrary: I recommend sidelines and a narrow repertoire.
In main lines you are at a disadvantage: the higher rated opponent will have studied those and will have experience with these from previous games.
With a narrow repertoire you accumulate experience.

I am lower rated, so take what I say with a grain a salt, but a piece of advice from a chess book I got is to not simplify positions against higher rated opponents. Keep your pieces on the board as long as possible, and keep the position complicated and defend well. Hope your opponent makes a mistake before you do. Again, I don't know, but I have a hunch @tpr is correct. You need to force a mistake, and it is easier to do that if you make your opponent calculate.

"You must take your opponent into a deep dark forest where 2+2=5, and the path leading out is only wide enough for one."

It comes down to hard work. Expose yourself to serious chess the masters play.

Well. People now memorize AlpfaZero openings. Whoever remembers more, wins.
@Sarg0n Please improve your puzzle rating. All titled players have at least 2500. Good ones have over 3000. Even I, a novice chess player, sometimes hit 2100 puzzle rating. Mastering tactics would earn you GM title. Good luck!

Online tactics rating: who the fuck cares? @hangrad

PS: I see your training rating is 1726 - good luck with your chess career!