I think that weakness will kill your chance for top-20. It's not that you're not good, it just because too many Chinese apply top-20. Based on your current material, your best choice is 20-30 schools or some Canadian school like York or McGill.
generally, everybody may have a chance. the game of MBA application is kind of a weird game with a lot of surprises the chance of success depends on how much you can and you will invest on it management experience is rather ambiguous, it is not necessarily related to your job, maybe something in your school days or research project narrower chance does not equal to less chance at least you can try, and allow yourself with some back-up choice