Certain product attributes set up in shopify are not pulling through to Google Merchant Centre eg Colour and Barcode. we’ve been trading on shopify for 2 years and have only had this problem very recently
I recommend you fill out the Google contact form: https://support.google.com/merchants/contact/shopify_3p_support_app
For a long time I have stopped using the google and youtube app, it’s just not very advanced and always has some kind of issue, for my clients I use: https://apps.shopify.com/multiple-google-shopping-feeds
Other than half a day down time during the crowdstrike issue, it has always been functioning correctly.