OVH tries to do that but I doubt that's waterproof. Probably easier to have an agreement with a US provider.

Having everything in the EU makes it much easier for them and is a selling point for many customers.

A US company can't force a German company to hand out data, I don't see what you mean by "waterproof".

The US government might not agree that they are two separate entities (they're not), and could take action based on that position (e.g. shut down the US company, ask the German government to compel the German company to comply with their laws etc.)

Microsoft has contracted their German Azure region to Deutsche Telekom (which is clearly a separate company) and claims to not be able to access the data. An arrangement similar to this (where basically the brand and technology is used by an actually independent company) could be possible.

Unless the US government slightly extends the law to include also the brands...