You have a problem? Those fights are not finished yet.
I bet he offscreened fights before chapter 1000 because he wanted chapter 1000 to be like that. He offscreened Luffy 1v1 Kaido because of Luffy new attack. Any other fight post 1000 was offscreened? Maybe Perospero vs Carrot and Wanda Sulong forms? Not sure about that one.