I cannot reach 1900

A good coach can be very useful for improving, but it's not a requirement. The coach can help you identify your strengths and weaknesses and find the appropriate lessons for you. Regardless if you use a coach or not, analyzing your games are invaluable, especially longer time control games. So is training tactics, solve for accuracy not speed.

Rook endings
another example

I’m going to say most coaching is useless. The problem is we don't need information about chess. We are buried in it. If you get a coach and say he teaches you a rook endgame, it’s a waste of your money. Buy a chessable course if that what you want. There are 10,000,000 resources out there including live demos. The same applies to anything else the coach wants to teach. Like openings.

So what can a coach do? Well, they should be teaching you how to study and therefore develop your chess vision/intuition.

Sooooo what does the OP want? A lesson on move 13 in the Sicilian Kan for 3 hours or a lesson on how to study chess as an adult. I’m going to guess it’s the latter and that most coaches don’t actually teach that.

https://chessmood.com/blog/to-succeed-at-chess-start-with-why
https://chessmood.com/blog/raise-your-chess-rating-by-cutting-your-losses
https://chessmood.com/blog/the-game-changer-question-in-chess
I hope those articles will help you.

One tip is learn a bunch of different traps in openings so you can set up or diffuse them. Also, if you find yourself losing in time scrambles a lot, then play more of the bullet variants. My bullet is 2300+ and blitz is trying to get to 2200. I can give you some extra ideas in a dm if you want.

@SrcEngine

I'll give you some hints if you really really want to go over 1900+ in blitz on Lichess
But no guarantees because maybe you are right and have reached your top level already, who knows
(e.g. Some people stay on 1100 rating for years)

*) Only play rated blitz when you feel good and are fresh (when feeling tired play casual or anonymous)
*) Avoid playing much lower rated players a lot (Losing against them will cost you), get slowly used to playing the higher rated ones and celebrate your good successes.
*) Play in the Arena tourneys
*) Try out ZEN mode on Lichess to avoid focusing on opponent ratings and rating gain or rating loss
*) Avoid losses which are not needed, for example when you go TILT mode, realize it and take a break
*) Check out what fits you better for time control, for example test 3 0 vs 5 0 vs 3+2
*) Analyze your games, especially those which gave you a puzzled feeling or where you lost without knowing why
*) Learn to think in your opponent time to have good moves ready
*) With each opponent moves try to understand what the move does, not just focus on your own moves
*) In heavy time trouble of your opponent when you still have lots of time, go for non standard moves when possible, and prepare a sequence of moves that you can play in one go.

And then the Lichess marathons are an interesting option to gain rating since you will meet much more higher rated opponents that are tired, or want to berserk all games and take risks to win points rather than rating gain, or e.g. just lost 5 games in a row and are confused but want to play on ;) (That is how I went over 2300 blitz a few years ago)

GL & HF !

Chessmood is a good idea. I recently signed up and I am impressed with them.

I always tell people that if you want to get good at blitz you have to work on your long game. It's opposite of golf. In golf, if you want to get better you work on your short game. In chess you work on your long game. I would suggest playing in the weekly classical arena that is 20 10. Take it serious. Use a board and pretend the board is in a real tournament and follow FIDE rules. When you are done with the game see if you can get someone to analyse the results with you. Not everyone can do the long game thing though. I know someone who use to be in my area. He never took a lick of lessons. Just played blitz. For some strange reason his blitz is 2300+. He's not much better than I am, but the sucker is fast!! If you can do that, more power to you. But most people need to work on their long game.

On another subject I saw in this thread..

"Prodigy" for the one that said it is someone who can pick up chess or another subject and master it quickly. Most prodigies if they care about chess reach 1900 within a few weeks or less. And then they blast off into the stratosphere. I once trained a prodigy. She was 22. I sat down with her every day for 2 weeks. She played almost consistently. And when I played she sat with me and asked me questions. This is no joke. She went from 1200 to beating 2200-2400 computers before my eyes. I was kind of mad about it. I asked her a few times how and she told me that I was stronger than I thought too. (I was 1950 FICS at the time and couldn't figure out how to reach 2000+). She "felt" I was at least 2000 and that I needed confidence. That actually kind of annoyed me more. But now about 16 years later, I am well into 2000+ territory, and when I think about the past I realized just how crazy good she could have been. I think she quit chess shortly after we stopped talking.. Prodigy is a washed up word and people use it too much these days. If I were to say someone today was a prodigy, the last one may have been Carlsen.

Play the <2000 Blitz tournament.