has anyone on chess.com get the rating of 4000

Rating of 4000? Is that even a question? Of course people have reached it. Its the first beginner milestone. Me and my buddy hit it within a week. Anything under 4000 is considered pretty amateur. I recommend practicing more if you are under 4000.
Says the guy with a rating of 400 in Blitz
Stockfish is about 4000, indeed.
It's almost perfect in both strategy and tactics.
Grab Stockfish and carefully follow its approach.
If you are unsure what other ways of playing lead to, make an alternative move and see how the engine reacts.