I don't think its like that. My understanding is that they will create a catalog with multiple services you can choose, and service provider will provide an unified API for those.
So you can take your prototype build on a server in $european_country_1 and publish it on the cloud of $european_country_2 once the dev is done without any change except the billing address.
If this is what you propose, this will be yet another stillborn project (Hey AI4EU!)
Yea.. so basically you have a catalogue but it's going to be up to the consumers or providers to find a way to stitch up a clearinghouse solution for dynamically orchestrated services from a multitude of providers. This is not only hard. It's near impossible. Without this crucial element, the platform is stillborn.