The issue is, when I try to save my complete dashboard in Export > PDF, it does not save more than 1000 records for the tabular panels. Also, any panel if exported as CSV also does not save more than 10,000 records. Need guidance please. Thanks.
That limit is hard coded as to not crash splunkd or python. You should really try to slim down your searches but as a workaround though if you are an admin on the search head you can pipe each of your searches to a csv.
It can then be found here $SPLUNK_HOME\var\run\splunk\csv