what to practice to cross 500 limit, I'm stuck here for a while
Looks like you already crossed it.
The trend line for the last year is very favorable. It does not appear stuck at all.
Learn and apply the most important principles of chess. - (core of my teaching)
Always blunder-check your moves.
Solve tactics in the right way.
Analyze your games.
Study games of strong players.
Learn how to be more psychologically resilient.
Work on your time management skills.
Get a coach if you can.
Hi.
I am rated over 2400 online (https://www.chess.com/member/ppandachess). I created a free course that will teach you a training plan to improve. Feel free to check it out: https://www.panda-chess.com/daily-improvement-plan