The EU (nay, perhaps every country) should be prepared to deal with Microsoft or AWS completely cutting them off from access to all their systems - what would be the cost and impact?
We are rapidly heading to not one Internet, but country-specific internets that may or may not bridge to other ones in some cases.
Realistically a US executive could be legally required to give an EU engineer a command that they legally couldn’t follow. At that point I guess we find out if the engineers’ national or corporate identities are dominant. I suspect the former in most cases, but who knows?
Google, AWS & Microsoft all nullroute the countries of Cuba, Iran and North Korea. Google also nullroutes Crimea.
So by using a cloud provider, you are participating in the embargo of Cuba.