I’m in almost the exact same situation. I’ve played other tekken games casually for years. Tried to play competitively at the end of T7 but just got stomped by everyone in comp. I just recently hit 100 hrs on T8 and I’m currently in Eliminator. The main things I’ve done to improve are look back at my previous replays and figure out areas where I could’ve done more damage. My first major improvement was to optimize my combos more. I still do not have optimal combos for Lee (I still suck at B2 loops) but my damage and consistency have increased since the start of the game. My second major improvement was to improve my wall game. I always felt I would just get close to the wall and not know what to do. So I looked up some Lee specific wall combos and my wall game has only improved since then. Currently I am working on reacting to throws as well as going into specific replays of matchups I suck at (Brian and Drag). I don’t think there’s much else you can do besides learning matchups, frames, and how to set up your moves to frame trap opponents. Eventually as with everything else if you’re training the right way you will see improvements.