How to report activity by individual API keys in Google Cloud > Google Maps Platform?

Question

We've experienced an issue recently where Google Cloud billing increasing greatly due to increased access to our Places API.

It turns out that we'd not properly used Credentials to restrict usage of our API Keys, which we're tightening up now.

BUT we're using about 50 API keys (one for each website that needs one), and it was far from easy to identify which API key was experiencing the recurring spikes in activity.

Yes, in the 'Metrics' section (https://console.cloud.google.com/google/maps-apis/metrics) we can filter by 'Credentials', but that's a cumbersome trial-and-error process to isolate the one(s) that are being hit the most.

It's possible I'm not looking in the right place or making the correct selections, but I would really like to see a text report/table showing an activity report (i.e. 'hits') per API key or Credential.

This would drastically speed up my ability to isolate the API keys with the spikes, and make adjustments to credentials/permission accordingly.

Does such a report exist, or should I be posting this somewhere as a feature request?

Thanks!

Ross