TL; DR: Using the Shopify Integration, how can I add a custom property to a profile created as part of the checkout flow.  This property is known by the website and doesn’t require user input.

Context:

I’m looking to use Klaviyo for review emails triggered after a product has been shipped. But I manage a multi-lingual store and want to make sure the user receives an email that corresponds to the locale they bought the product on. 

For context our site is a Shopify store built on Hydrogen and, to-date, I’ve disabled client side Klaviyo tracking.  I don’t want to enable it if I can avoid it for performance reasons.  I have a single Shopify store and Klaviyo instance for all of the regions the site is available in.

My plan to localize these review emails is to add a custom property called `locale` onto the user profile as this closely aligns with how we show different content on the store itself.  I’ve noticed that when a user purchases a product a profile is created, and it’s populated with their checkout data.  What I’m wondering is, “Is there a way to inject additional props into the checkout process that will automatically get added to the user profile that Klaviyo creates as part of the checkout flow”

I haven’t found a documented way to do this, and if there isn’t one. Then I assume I’ll have to enable client side tracking and add the property to the anonymous user profile prior to purchase, and figure out how to associate that to the user post-purchase.

Looking for any help or documentation on the above.

Thanks for your thoughts!