Why do you have any more confidence that China would willingly give their top tech anyone else without conditions?
China, like the USA, is an aggressive mercantilist economy. As such, they will use OSS to gain advantage until it does not serve their interests anymore, at which point they will rugpull you too.
Ultimately, IMO, the world will align in development blocs with major players and allies developing parallel lines of AI, one of which will be the likely winner. China is playing the magnanimous world leader card at the moment because it gives them advantage and costs them little. When it gives their opponents more leverage against them, that magnanimity will end.