I think you should be able to recreate the dashboard-reports in the data explorer and add in a generate_series to populate a full list, including dates with no data.
You can find the SQL for the dashboard reports by browsing the dashboard-sql tag, or there’s an overview in Admin dashboard report reference guide
If you have a specific one in mind we may be able to give an example if you need one?
Also, there’s an existing #feature request to allow including ‘empty’ dates in the reports themselves if you’d like to add your vote to it: