How to improve at chess?

So I used to be 1250 in chess .com I started as an 800 during pandemic and played for a few months back then. Then I quit. Few months ago I heard the news that Gukesh became the world champion. So from December I started playing chess and I just kept winning crossed 1800 2 weeks ago. But then I was on a losing streak went down a bit got back to 1800 and then again got into a losing streak. I raged and deleted my chess .com account. I had watched a few videos of Gotham chess explaining London system Englund gambit and French defensee. How to improve in chess. I didn't even know how I gained 600 rating point suddenly after not playing for years. Seriously guys how to improve.