If it's a prelude to war, why has neither nation recalled their ambassador or expelled the other's citizens?

He doesn't have the constitutional authority to issue this order (though I'd love to see companies follow it anyway), but similar orders have been given by congress numerous times without a military follow-up. Recall the trade war against Japan in the 80's and 90's.

As for China being dependent on selling their cheap crap to the US, this is true, but they are trying (with mixed levels of success and failure) to change that. That's what BRI is. A few of China's bigwigs think they're going to use that to rule the world and the West certainly thinks that what China is up to, but in reality it's a desperate bid to create access to markets other than the US to avoid collapsing if we drop them like an ugly prom date, which we're doing before BRI is finished.

As for the potential for military action, I don't see that the US will start one (because we don't need it: we're crushing them), and I doubt China will be stupid enough to start one because beneath all the strum and drang, they know they lack a snowball's chance in hell of winning one.