I am currently facing the exact same problem. We have an instance of Data Cloud on which we have setup an Ingestion API. The data get to the DMO, and we have a Data Cloud-Triggered Flow that should ingest these data to update a record, but nothing happens.

We have also setup the debug logs on the workflow user and verified the permissions, but nothing has helped so far.

By any chance, did you find the root cause of the problem ?