and for those who donst wanna scroll through the entire game i believe its on move 36.
why is promotion to a rook best?

i didnt actually make the promotion i was trying to be cute but you can see that if i promoted to a queen the engine says its a bad move.

I dont understand either way as both my rooks would be lost regardless in this following pattern, but why is it better to under promote to a rook? Is it just because the engine sees losing the queen as a bigger loss? someone explain please lol
Common sense would indicate that both Queen or Rook promotion is the same (or Queen is better) because after promotion, then Rxb1 will happen anyway. The engine shuffled between Rook or Queen at the lower depth analysis (since they are the same), but once it runs deeper, then it calculates forced checkmate with either promotion being the same.
At depth 50, it shows Mate in 18 with Queen or Rook promotion.
I dont understand either way as both my rooks would be lost regardless in this following pattern, but why is it better to under promote to a rook? Is it just because the engine sees losing the queen as a bigger loss? someone explain please lol
https://www.chess.com/game/live/89954993591