I can teach you EXACTLY how to think during the game (opening, middlegame and endgame). Your chess understanding will never be the same and you will improve a lot. I charge €10/h, but if you can’t afford too many lessons, don’t worry. I can teach you a lot in an hour. Here to help if you are interested.
If you want to study by yourself, read ‘Logical Chess’. It is really instructive book. You have it on youtube as well: https://www.youtube.com/watch?v=0eTB7oHeRgM&list=PLUrgfsyInqNa1S4i8DsGJwzx1Uhn2AqlT
Did you give up chess? Don't care about your ratings. Play for fun. Paradoxically, the only way to improve is to practice playing and you will do that if you find chess fun to play and forget about the rating. So, not caring about your rating and about your strength level would be a good way for you to get better.