I need to know can I able to avoid or restrict to push the Native fills for certain ads which are served from DFP_DS or Admob if they are not relevant to our app on iOS.
For say, I am getting the amazon music ads and I am not interested to show certain ads in our app. How can I restrict this to fill in the app.
I am getting this in the release mode as well.

You can set up a blocklist from your adnetwork / adserver user interface based on the category, the advertiser or other criterias, as detailled here.