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: