call in U.S. debt and dump their dollar reserves

They can't do much about the US debt they currently own, but they CAN stop buying future US debt. THAT would drive up the interest rate needed to sell that new debt to others. The debt they currently own will just get held--if it has a fairly short maturity. Long-term debt can be sold on the secondary market--if the price received is reasonable. But, if many other countries are *also* dumping US debt they currently own, then the market price could be significantly lower than it used to be--and then they choose to hold it (for now).

U.S. companies will be expelled from the European market.

Don't know about this one. IMO, they will not be "expelled" per se, but it is more about which technologies are involved AND who created that tech. US companies could be "cut off" from gaining access to tech developed in Europe. THAT could get VERY EXPENSIVE.

Remember: The US has massively REDUCED R&D INVESTMENT as a govt policy, thus future major developments will mostly NOT come from the US but from other countries.