Tariffs of more than 100 % to be paid by overseas vendors essentially mean: You can give us your merchandise for free plus some extra money for our government. Presents instead of debt. Only a "stable genius" and his fans will believe in that.
China is using economy to try and break the expensive US military dominance. They copy what the US and Europe did to the Soviet union.
The tariffs won't, of course "be paid by overseas vendor" any more than Mexico "will pay for the wall". Purchasers in the US will pay the tariffs, to the US government.
China isn't "using the economy to try the expensive US military dominance". China could, and I expect will, use it as a big pressure point on the US. Expect China to invade Taiwan, possibly in my lifetime; China is already building enormous landing barges/jetties.
Putin is successfully playing Trump, and it is in China's interest not to prevent that.
As for tariffs, early warning of climbdowns won't be seen in the stock market. Climbdowns will be forced by the US Government Bond market. History lesson; the UK PM, Liz Truss instigated similarly stupid libertarian economic policies, which detonated the UK Government Bond market and forced her out of the window.
The other big "known unknown" is the enormous shadow banking sector, e.g. hedge funds and private equity. Wait until they detonate, and there will be a repeat of 2008/1930.
Hence overall the tariffs aren't the biggest problem, but they are the visible indicator of serious problems. Tariffs can be instantly reversed, once it is defined/stated that the objective has been achieved.