I don't think the latter part is true. AFAIK GDPR does not give you the right do have your data owned or processed by an EU entity. GDPR does not say that.
It doesn't matter where your data is stored or processed, Google must still follow GDPR rules for data about EU residents. The first part of the comment is correct.
I'm not actually completely sure why some companies do this whole EU data controller seperate company thing. I guess for organisational or legal simplicity?
(Edit: I reworded to hopefully remove ambiguity)