How can I improve quickly?

Improving Your Chess - Resources for Beginners and Beyond...
https://www.chess.com/blog/RussBell/improving-your-chess-resources-for-beginners-and-beyond

Continue playing and have fun.
Secondly, analyze each game afterwards.
Lastly, keep up with your tactic puzzles everyday.

Practice, practice, practice. The analysis is such a great feature to learn from and most importantly have fun

#1
"I’ve been doing drills, lessons, puzzles, and etc." ++ So that is not the way
"I’m fairly bad at openings, and endgame."
++ That does not really matter. You blunder often. Always check your intended move is no blunder before you play it. That little mental discipline alone is enough to get to 1500. Do not hang pieces or pawns.

But with the limits to them, I’ve been playing matches against other players, but I don’t see an improvement. In fact the only thing I see is a lack in skill.
I’m fairly bad at openings, and endgame.
Hi there. I looked at some of your games. I think your problem is about hanging pieces. you must be paranoid about undefended pieces. when your opponent move a piece, try to look at what that piece is attacking. try to develop as quickly as possible but you must keep your pieces defended. and try to castle before move 10. you will improve gradually.

I think you need a training plan, its not enough to just learn random things, you need a plan and structure. A Chess book is a good tool to get structure in your training. Also like other people said analyze. I analyze every single game I play to spot my mistakes, think why I made them, and how I can avoid them in the future. At first I would learn 2 or 3 openings (1 with white and 1 with black) and try to master them. You also should focus on a few things at the time not all at once. Me for example I try to improve my coordination right now so I often do coordination training. Also I want to improve my decission speed so I do puzzle battles. Think about what you want to improve what you lack off and choose the training to achive that goal.

Continue playing and have fun.
This is the most important advice you could possibly get. If you do these things, progress will come automatically. Not everyone is destined to become a "good" or "very good" player. But anyone can become an adequate player. There is no rushing the process. Just play and have fun. If you are not having fun, it's pointless to play chess. Too many people come here and are in such a hurry to climb to the top that they seem not to be enjoying the game.

Hi! My name is Lauren Goodkind and I’m a respected chess coach and chess YouTuber who helps beginners out :
https://www.youtube.com/channel/UCP5SPSG_sWSYPjqJYMNwL_Q
I'm glad you want to get better.
Here’s some ideas to help you get better.
-I’ll be happy to analyze one of your chess games for free for my YouTube channel, since I love to help beginners out. Share one of your games with me! This is a great way to get better!
-I recommend two books for you: “50 Poison Pieces” and “Queen For A Day: The Girl’s Guide To Chess Mastery.” Both books are available on Amazon.com. Both books are endorsed by chess masters!
-If you are serious about chess, I highly recommend you hiring a chess coach to help you.
-Also consider all checks and captures on your side and also your opponent’s side. Always as, “If I move here, where is my opponent going to move?”. Do this for every single move!
-Play with a slow time control, such as G/30 so you have plenty of time to think before every move.
I also offer 500 two-choice puzzles on my website: https://www.chessbylauren.com/two-choice-puzzles.php

https://www.youtube.com/channel/UC6hOVYvNn79Sl1Fc1vx2mYA John Bartholomew is really good to watch. https://www.youtube.com/watch?v=U2huVf1l4UE&list=PLl9uuRYQ-6MCBnhtCk_bTZsD8GxeWP6BV
You can learn how to play solidly just watching these.

It looks like you made an account last Friday and until now you have only played 11 games. The answer to your question "how can I improve quickly" is that you can't. Chess is a difficult game and will require time, effort and dedication.
The advise given is so far is good, but not applicable to you yet. After looking at Game & Game., I believe should learn the basics first. You should play more games and do ore lessons, develop a feeling for how the pieces move. Just enjoy the game and have fun. If you still enjoy the game in a few weeks time, revisit the answers given here and go from there.

Step 1. Stop playing bullet! You can't get better at playing chess if you spend one seconds on each move. You really can't.


Bottom line that I see when looking at your games is similar to what a few said above. You need to focus on how you are thinking in a game. Training plans are great, but you don't need to know the Windmill tactical motif when you're hanging your queen on move 4.
Start by playing slower time control and going through a list of things before you make a move. The following is paraphrased from The Fastest Way to Improve at Chess by James Demery:
1. What is the piece my opponent just moved directly attacking now. Do I need to respond or is my piece defended? Did the piece my opponent just moved leave a piece or key square unprotected?
2. What checks or captures can happen in this position from me or from my opponent?
3. What pieces are undefended on the board? (both yours and your opponents)
4. What's attacking what and what's defending what? At first you can think just in terms of pieces, but as you can understand more information, you will think of it in terms of key squares too.
5. Are any of my opponents pieces vulnerable to a coordinated attack?
Try thinking about the position in these terms. Also picking up a book like My System by Nimzovitch or Lasker's manual of chess can be good resources. Watching Daniel Naroditsky on youtube. Just to learn the basic opening principles and how to apply them (it's really as simple as, try to mobilize all of your pieces faster than your opponent while minimizing pawn moves that will weaken your position). There is no need for you to waste your time memorizing more than 4 moves in your favorite openings.
But with the limits to them, I’ve been playing matches against other players, but I don’t see an improvement. In fact the only thing I see is a lack in skill.
I’m fairly bad at openings, and endgame.