They would probably need a anchor client that would allow for predictable growth at scale - AWS always had Amazon.com GCP had its gmail and other workspace apps.
Ideally the varoius goverments in the EU would commit to only hosting their work on them , however from one article read recently even the rules they come up with to test sovereignity claims are gamed to benefit the US providers.
Yep,hopefully their API offerings are industry compatible and requisition of resources for clients is smooth. Would also help if they can onboard similar sized operations that are currently doing their own hosting or using one of the non-EU clouds.