In general, the answer is "no." Let the software do the work.
Also, when photos and videos are deleted from either the app or the portal, those files are not deleted from the camera's SD card. Format the SD card to delete the files on it.
By default, photos and videos stay on your phone for 30 days. The first time you open the app each day, all photos and videos over 30 days old that you have not saved are deleted.
If you don't want that many files on your phone, set Purge Days in the app to something less than 30. Set a number of days that is long enough for you to make sure you save anything to your phone that you want to keep.
Photos and videos are automatically deleted after 30 days. At midnight, all photos and videos that are 31 days old are deleted. Just let the portal do the housekeeping under most circumstances.