def 1
Duo’s rating

Same.
I guess he has a rating of 2400 rating. In the starting, he plays as a 1200 rating player but in the middle game and end game, he plays like he is 2500 rating.

My score against Duo currently is like around 15-20 losses, 2 draws, 0 wins, that's why I'm angry Duo plays so trash sometimes but swindles me every time, for context I am 1800 rapid

finally I won 1 time, https://www.chess.com/game/computer/96387451 I won once, I lost 17-22 times against Duo, I drew 3 times before I finally won!
I won 3 times against him somehow.....
Three times in a ROW
Play a language opening?