Yes, it is possible in dashboard designer to set today's date as default value in Datepicker. Please follow the below steps to achieve this.
Step 1: Select “Range” type in the property window of Datepicker.
Step 2: Select “Relative Dates..” from the dropdown list of settings.
Step 3: Select “Days” option then “Today” option as highlighted in the below screenshot and click on “Add” button to add this in the relative date option.
Step 4: You can see the added relative dates in date picker as in the below image. Select “Today “ option as highlighted in the below image to set today’s date as default.
Output: Now preview the dashboard. By default, it will render the data of today’s date.
To know more about Relative date configuration, click on the link.
Let us know, if you need any further assistance on this.
C Jenitta Rachel