Yes we can buy our way out of debt with China by either simply money transfer from fed or even printing it and sending it in crisp clean paper....
But,!!! it would weaken the dollar and boost inflation like it was on nitrous.
And the "rigged" you speak of is exactly what China does, the US does and so does every other top 20 world economy. It is all fair game in the cut throat game of world economics. It makes sense for the us to have China holding or credit cards. If the dollar is weak then we pay them very little in the end and if the dollar is strong our economy buys the tariffs and the interest is paid in money transfer like you are describing. Our deficit is a more delicate beast though. That pushes interest rates around and that means more lost revenue.