"The deal must be blocked if there are no legal guarantees that Dutch data cannot be accessed in the U.S."

This would be a very mild response, given that the Dutch government recently attempted to take control of chipmaker Nexperia [1], where much less were at stake.

Even if guarantees are given, who is going to enforce them against an order coming from the US government?

[1] https://nltimes.nl/tags/nexperia