The docs explicitly describe this cloud's independence from the US.
> The AWS European Sovereign Cloud will be capable of operation without dependency on global AWS systems so that the AWS European Sovereign Cloud will remain viable for operating workloads indefinitely even in the face of exceptional circumstances that could isolate the AWS European Sovereign Cloud from AWS resources located outside the EU, such as catastrophic disruption of transatlantic communications infrastructure or a military or geopolitical crisis threatening the sovereignty of EU member states.
> The AWS European Sovereign Cloud will be capable of operation without dependency on global AWS systems so that the AWS European Sovereign Cloud will remain viable for operating workloads indefinitely even in the face of exceptional circumstances that could isolate the AWS European Sovereign Cloud from AWS resources located outside the EU, such as catastrophic disruption of transatlantic communications infrastructure or a military or geopolitical crisis threatening the sovereignty of EU member states.