How do I upsert data into SharePoint list from Synapse table using logic app?

Question

This is my first Logic App design. The app succeeds on the first execution to get rows from synapse and insert them to empty SharePoint list. When I run it second time without new rows from the source so it finishes without appending no new records to SharePoint list, it fails when appending array values from SharePoint list. I can use help to see where things go wrong.

This is where it failed

Here is the logic I used array to pick unique identifier from SharePoint list and check if it exists at source.

Thanks Sam