Google is doing this. German and French companies are building a datacenter to GCP standards, will license the code and run essentially whitelabel GCP under full jurisdiction of the EU company. Google can only push updates with their approval and has no visibility into the operations.
They get documentation and playbooks (which are pretty good), source code access, and of course direct channel to the "mothership" engineers for support.
I'm sure early days will be painful but there is no reason for this not to work.
https://cloud.google.com/t-systems-sovereign-cloud?hl=en