China holds <$1T of US debt. Sure, they're the second largest foreign holder of US public debt, but we could easily replace that debt if needed. The Treasury itself bought much more than that after the 2008 crisis, and we could do it again. Private citizens hold way more than China does through mutual funds and whatnot, and investors would buy more if rates go up.

The real problem is that interest rates for public debt is going up, so we'll end up paying a lot later share of our budget toward interest if we don't reduce our debt load. Those older, cheap Treasuries will be maturing over the next decades, so the time to act is now. I'm in favor of raising taxes somewhat and cutting spending across the board (I think a lot of it is waste that could be caught in audits). But China doesn't factor in at all when it comes to debt concerns.