Hi there,
I have a similar (not identical) issue to what is outlined here: https://community.shopify.com/c/ecommerce-marketing/google-product-reviews-feed-not-showing-stars-issue/m-p/1288866
In short, I use the Shopify Product Reviews app, and have over 50 reviews - I want a Google star rating for my shopping listing, and have found out that the Shopify product review app does not qualify as a ‘approved aggregator’ - so I need to upload a ‘xml file’ to my Google Merchant centre, containing the review data from Shopify Product Reviews. I have no idea how to do this or what it encompasses. Google have told me they can not help and I must do this myself or ask Shopify, but I wondered if someone here can help please!