If you want a 1929 on steroids, do that.
Mobile phones (android could be forked I guess, Apple would be out).
Payment processing - shouldn’t be a problem if the U.K. is on side, one industry which isn’t been completely bought by America
I suspect China will jump at the chance to assist and Europe will be stupid enough to take it.
Jokes aside, isn't pushing Europe into China's hands exactly what the USA doesn't want? Part of the motivation behind Venezuela was they were getting too cozy with China.
It's impossible to stand alone and still have access to all top tech in todays world. US will obviously rely much more on china without EU trade.
EU is currently dependent on US for software/cloud.
US is dependent on EU in advanced machinery, precision tooling and high end manufacturing equipment.
The US imports massive amounts of chemicals, drugs and vaccines from the EU.
Both regions would look to china for replacements probably.
A major downside and risk for Europe is that they would have to get the share LNG from the US from elsewhere, as it's not self sufficient energy wise, but this would most likely not come from China.
“Quickly” is unlikely, but it has already started.