u/Fresh_Astronomer_359

I have been playing for 5 years now mainly on chess.com, I have reached within 2 years 2000 on bullet and 1900 in blitz( starting from 800). I never studied any theory I don’t know anything theoretical about openings or end games. I just improved by playing and analyzing my games.

However, now I have been stuck at 2000, for like 3 years. What would you advise me to learn ? What good openings are efficient, and what theory I should study to break the 2000 and reach 2500 maybe.