Yes on that scenario is my anwser based..
First use the Search API from Hubspot to search for a Deal with property ShopifyId;
If that one finds some records, it can return the ID’s of the Deals. Then you can use this ID’s in the Deals API to udpate the Record with the values from your ERP system.
But what if there are more deals with the same ShopifyId in Hubspot? Do you have a check for that?