Is AdGuard for Android pointless since it uses a VPN slot?

The DNS filters you’re using by themselves are fingerprintable. What is and isn’t blocked is fingerprintable. Also, just using a custom DNS with a VPN lets them know what VPN and DNS provider your using at the same time. Not everyone does this and likely not with the same combo. But you are right. Blocking ads goes a long way, but that can just be achieved with a VPN that has its own block list. Proton can do this for example. While yes, a more extreme custom DNS may block more I’m not sure if it’s worth the downsides. But like I said in my last post, that’s just my opinion, do what ever you feel is best for your situation.