No customer data is shared with data with third parties (outside of Google Analytics, of course).
We do request customer data from Shopify because we send the shipping country, city, region, and postal code to GA4 because GA4 doesn't provide location data server-side.
We store the Shopify webhook data for 7 days for infrastructure reasons (replay dropped events. debug issues, etc), after which it is deleted. We store non-personal identifiable information (client ids, sessions ids, etc) for a maximum of 14 days. Again, none of that data is shared with third parties.
All data stored beyond 7 days is completely anonymized, ie al customer data is completely removed.