You can use our new v2 Insights API to gather more information about your pipelines for a specific branch. This section of the docs has more info: https://github.com/CircleCI-Public/api-preview-docs/blob/master/docs/api-changes.md#get-insightsproject-slugworkflowsbranchbranch-name
Can you check that out and see if it includes the information you’re looking for?