Reached 1600 chess.com within a year starting from 600 and 2000 Lichess. What I believe to be more important is how you do something rather than what you do. What I mean is, someone can play many puzzles or games but if you are just blitzing out moves in puzzles even when you haven't calculated to a guaranteed advantage then you aren't learning anything. You are just exploiting what you have learnt over exploring by trying to look for patterns you wouldn't normally look for. Constantly even in complex positions people blitz out moves only to blunder.

This is why I don't recommend bullet to anyone.