Parsing WFS write transaction response in OpenLayers

When a user modifies the geometry of a feature on my map, I am using WFS to write the new modified feature to the GeoServer. I have verified that this works: the modified geometry is indeed saved in the database.

Also the server responds with an XML payload that, inside a <wfs:TransactionSummary> supplies the correct number of updates (1), deletes (0) and insertions (0). I know that by inspecting the "Network" tab on my browser’s developer console.

My question is how to parse this response in JavaScript using the open layers library. I have found the readTransactionResponse method on the ol/format/WFS class but I am not getting the results I expected; instead I get an empty object ({}).

Here’s the code:

 const featureRequest = wfs.writeTransaction(
    [],        // inserts
    [feature], // updates
    [],        //deletes
    {
      srsName: 'EPSG:3857',
      featureNS: 'https://geoserver.anon.com/',
      featurePrefix: 'coredb',
      featureType: 'eae_field_geospatial_data'
    });


  
  return fetch('https://geoserver.anon.com/geoserver/coredb/ows', {
    method: 'POST',
    body: new XMLSerializer().serializeToString(featureRequest)
  }).then( (response) => {
    const tr = wfs.readTransactionResponse(response);
    console.log(tr);
    return tr;
  });

The above code prints {} on the console.
Any ideas?

return fetch('https://geoserver.anon.com/geoserver/coredb/ows', {
  method: 'POST',
  body: new XMLSerializer().serializeToString(featureRequest)
}).then( (response: Response) => {
  return response.text(); // response is a Response object in this block
}).then( (response_as_string: string) => {
  // response_as_string is a string in this block
}