China has been trying to build up domestic markets for the past several years. With the US imposing high tariffs on Chinese goods it stands to reason that they’re not in a position to import from Vietnam, etc. because there will be domestic overproduction.

Could be, but China's imports from the US where not much (6% of their total) and cannot be easily substituted from SEA countries, as they were mostly importing a ton of agricultural stuff (soybeans, corn) plus fossils.

I understand 6% of china may be a much higher percentage of, say, Vietnam's export, but I just don't think Vietnam can produce that much more of that, quickly.

https://atlas.hks.harvard.edu/explore/treemap?exporter=count...