Chess questions...

Hello chess community I am new to chess, so I ask for your advice:

Context: Lastly after four months of diamond subscription on chess.com I realized that I have completed every single lesson, did many puzzles and played some games. This made me think if that was as helpful as I think since I started about at a rating of 500 and got to 1100 (depending on the day I play). But I want more, and I want to get to 2400, but the problem is that I do not exactly know my errors while playing chess even after analyzing the game I understand my mistakes but I the next games I make the same number of mistakes. After watching a few videos, I have come around an app called which made me interested so I would like to ask a few questions to those who used that app.

Is this even legal? Aimchess tracks your account which is kind scary for me, what if chess.com finds out and decides to close the account, is that even possible? How do aimchess take track of your games? Finally, how can that be legal if chess.com offers you a membership to analyze games, but you choose to subscribe to a website that keeps track of your game costing you less and giving you more features?
Is aimchess legit? I was thinking isn’t that a scam or a simple money grab or does it really help you and improve?
If you have been using aimchess what is your opinion on it? Is it good, bad?
What would be the most efficient method of getting better at chess (besides playing more games, doing puzzles, reading books, analyzing games)?
What is better aimchess or diamond membership of chess.com?
Is this real that aimchess was sponsored by Magnus?
What is better chess.com diamond membership or aimchess?
I would really appreciate if you answer some of these questions. Thank you for your time, have a great day!