Citing shipments from China via Vietnam to evade US import tariffs, the US added tariffs of up to 400% on Vietnamese steel. This might suggest the US will pursue major trade concessions from trade negotiations with China or else move to nearly 100% tariffs.
China has bigger ports with bigger volume. Boats go there last before going to la/longbeach. No boat would go Hong Kong => ho chi minh=> la/lb. Bigger ports get faster shipping.