DNS changer ios app

DNS changer (dummy vpn to change the dns ip address) I would like to create an app that would change the dns for the ios device to my dns service using a dummy vpn tunnel just for the purpose of changing the dns What im looking for: A simple display page with a connect button at the bottom Backend service that would control the dns ip address provided to the client ( for changing the dns ip if needed) and also to store data about phones for registration purposes The app will be totally free for two weeks then wouls require a a monthly payment using inapp purchase To make things easyer you could google github of adguard for ios its a sample code of how things are working or if your wondering how the dummy vpn service would work Thanks