GTM not sending user events to Retail API event though tag fires successfully

[t_saint_clair]

I'm currently looking for support using the Retail API in GCP. Specifically we're trying to set up the Recommendations AI by sending real-time events via GTM using the Retail Cloud Retail tag and have hit a wall. So far we've done the following:

1. Project set up in GCP with both Retail API and Recommendations AI API enabled
2. Created API key
3. Imported catalog data
4. Set up the Cloud Retail tag in GTM with all of the relevant information found in this doc: https://cloud.google.com/retail/docs/record-events#gtm. The tag is leveraging the GA4 ecommerce object via a Custom JavaScript Variable that is translating the onsite dataLayer into the GA4 format.
5. Tested the tag in Preview Mode, tag fires successfully and the ecommerce object variable gets populated with the right info
   

   I thought maybe it was an issue with price being an number vs string, changed it to string and that didn't help. Also was unsure if the event name not being included would effect it but the docs say that it can leverage the GA4 ecommerce object which this is.. maybe we need to rebuild the object specifically for Recommendations API with the event name 'detail-page-view'? 

At this stage we've been monitoring GCP logs to see if any events are coming through, even trying to come through but failing, and nothing is appearing in GCP. No idea what is not working, would sincerely appreciate any guidance if you have experience with this tool. Thanks in advance!