Hi Girish - There might be better solutions for your user community than an interactive filter for by incident number - they'd be searching through perhaps hundreds or thousands of record IDs and I think that might create a performance issue on the search and then rendering results into your dashboard.
Your users might find more value in an interactive filter by the User (either Caller or Assigned To). I believe this is already available, there's an example in my PDI but the docs also have custom interactive filters on the task records: https://docs.servicenow.com/bundle/rome-now-intelligence/page/use/dashboards/reference/r_CustomPublisherExample.html#r_CustomPublisherExample
Alternatively, you could create a user dashboard with reports that have dynamic filters (each report has user id is filtered by the logged in user id and PA indicators can also have dynamic filters). https://docs.servicenow.com/bundle/rome-platform-user-interface/page/use/using-lists/task/t_DynamicFilterOptions.html
As for the few specific incidents in the dashboard drilldown, it may be helpful to look at the list view that a user has access to and see if the filtering options (show matching, hide empty) are available or secure and if the user can add to the existing filters.
Hope that helps!
