plateau at 750 blitz any tips

My recommendation is to play longer time formats.

In this game for example, you managed to lose the game with 2:58 minutes on the clock remaining. In a 3 minute game that lasts 30 moves you have 10 seconds per move, in longer games that last 60 moves you only have 5 seconds per move. That's not enough time to make an informed decision, but at least you can scan the board for obvious threats. However, when you play more than one move per second, you have no time to think. At all.

The same happened in this game. You have 2 minutes left to think, but instead of using that time you simply blunder your Queen. Did you blunder your Queen because you are a terrible chess player or because you only spent 2 seconds on that move?

Top level chess by GM's make it look like Blitzing out moves can lead to good chess but that's misleading. They can only do that because they have seen positions and patterns before, many many times. Without that foundation, you can't play good moves in a couple of seconds, let alone in under a second.

For every move, you need to work to determine the best move. It's a simple process, but requires calculation. You need to look at the board and make sure you see everything. Then you need to identify candidate moves. Finally, you need to evaluate the positions that follow for each move. Only then will you know you have found the best move. That will take time.

That's why I recommend playing longer time formats.

Play a lot, analyze your games, and primarily study tactics. Your knowledge of openings, endgame, middlegame, etc. will come from analyzing your games and going over grandmaster games. Only study one of those specific topics if it is clear you are specifically losing because of that topic.

Source: https://www.gautamnarula.com/how-to-get-good-at-chess-fast/

As a coach, I can help you with any part of that process, as well as teach you EXACTLY how to think at every stage of the game. Good luck!