That doesn't seem to be true though. There are multiple countries outside the EU that have an adequacy decisions regarding their privacy laws like: Japan, South Korea, Canada, UK, Isreal, etc. They can host EU data without issues.
The only reason the privacy shield agreement was thrown out was due to lack of safe guards from US intelligence.
Even without the privacy shield, US companies would still be able to store EU data in a country with an adequacy decision if it wasn't for the CLOUD act. This seems more to do with US law wanting access to EU data.
Is there anything restricting US companies from first transferring EU data to a country `A` with an adequacy decision and then transferring that data to the US (assuming `A` allows this)?
The only reason the privacy shield agreement was thrown out was due to lack of safe guards from US intelligence.
Even without the privacy shield, US companies would still be able to store EU data in a country with an adequacy decision if it wasn't for the CLOUD act. This seems more to do with US law wanting access to EU data.