Same here which is why I don't have alot of the tracking protection & blocklist enabled for my device bc of that issue there & it blocks certain game ads too. 

That means it’s working  

There are ways to allow certain domains that are required for the functionality of the anti-adblocker checks but it takes time and testing to figure out.

Just allow domain

pagead2.googlesyndication.com

You can't. Nextdns works like an adblocker so if you're using it and the site is smart enough it will be detected