Google would have to redesign their corporate structure so that EU customers of Google EU are never subject to US law, with no US-owned business anywhere in the subsidiary chain. Imagine that this is the current chain:

Alphabet (US) -> Google (US) -> Google (EU)

Under such a structure, Google (EU) is not GDPR-compliant, and will need to drop all upstream inheritance of (US) to comply with this ruling.

I am not your lawyer, this is not legal advice.