You didn't beat a real GM, just an AI. And considering your rating I do not believe that you did it without help, such as best moves. If you didn't cheat congrats, but it's unlikely, as 2000's have a hard time with this bot.
how I beat a GM
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this is not cap if you don't belive me then check the details for the rating here is the link https://www.chess.com/analysis/game/computer/59045991?tab=review