This is bad.
FB deduplicates events in three parameters:
Event name
Event ID
fbp
Since Shopify integration and your setup will send different event id - very often these events will not deduplicate, meaning you will have overreporting.
In test mode you can de-duplicate them because of the same fbp, but it won’t work 100% of the time.
Have you, or do you know anyone who has ever successfully implemented sGTM with the same pixel and parallel running with the native Shopify integration?
Or am I just wasting my time trying to make this work?
In case event id’s are the same - you can do that and I’ve seen similar settings.
But to be honest this makes little sense, because even if you send more data for a user or a product with additional events from GTM - they won’t be taken into account by Facebook.
Facebook primarily counts the web event that came first, all further events are simply deduplicated and the data within them is not counted.