We have also struggled with the lack of notification on for approval results - specifically around when you submit an object for approval and not receiving a notification if it was approved/rejected. I created a flow in Fusion to do a tagged update to force an email. If you want to create a report or view, there are a couple out of the box fields you can add to your view to get some information. For issues that are pending approval, you can add Approvers and Status. If the approval process has been completed, you can add Approval Path Completion Date to see when the approval process was completed. Below is a quick report I put together with 3 issues (new - not sent out for approval, in progress - pending approval, completed - has been approved) so you can see the fields. For more advanced options, you could look at doing a journal report or using advanced report (collections).