Report on Group Attestation for Auditing purpose

Recently, while working with a prospect, I received a use case in which they were looking for a report on group attestation. The report should contain the following information:-

- Date on which the attestation was done

- Who did the attestation?

- What were the actions performed during the attestation process? What information was changed during the attestation process?

I provided them a workaround with the history summary export however, for the attestation actions, firstly it doesn't contain all the changes done during the attestation process (who was added or removed is not present in the export even though it is present in the history shown on portal and console) and attestation actions are not easily recognizable when looking at the export. 

A report should be there for auditing purposes to keep track of the attestation actions.