Ads integrations for Android

Hi,
i want a simple code with 3 ad networks and control the ads from json server ( like "enableAds":"true or false") and if it is enabled show one of three ad network (like :
"admob":"true",
"ironsource":"false",
"applovinmax":"false",)
and :
Ironsource mediation with ( Facebook ads + unity ads + admob + applovin)
Admob mediation with (unity ads + applovin + facebook)
Applovin max with (Facebook + unity + admob )

and ad units i want : banner + interstitial + native + rewards

and when the interstitial showed the next interstitial should be loaded for the next show.