Google, Microsoft, Amazon et al should be hard at work lobbying the US government to scrap stuff like the CLOUD Act and introduce privacy safeguards as strong as the EU's, or they can all forget about winning in the EU.
Yes, AFAIK, the existence of the CLOUD Act and its impact on GDPR has yet to be decided by the European courts, but if previous verdicts about Safe Harbour etc are anything to go by, the fact that an individual European citizen lacks practical legal recourse when their data are improperly handled by US companies, suggests it won't be long before cloud solutions operated by US-owned companies, even if those are EU subsidiaries/joint ventures etc, are declared non-GDPR, and as such will be off-limits to almost every operation in the EU