Do I need to connect Google for each business?

Yes. The Google connection is per business: each location must have its own Google account connected (or whichever account is an admin of that location in Google Business Profile).
In practice:

• If you have multiple businesses, you'll need to connect Google for each one during onboarding or from the corresponding menu section.
• The Google account can be the same (if you manage multiple locations with one account) or different (if each location is managed by someone else or another account). The important thing is that the account you connect has admin permissions for that location in Google Business Profile.
• Without a Google connection for a business, you won't be able to view reviews, respond with AI, edit the Google profile, or see full analytics for that business.