Hello,
We can help you. Our plugin Universal Mobile Ads for iOS & Android is exactly what you need: Universal Mobile Ads for iOS & Android - Marketplace - Unreal Engine Forums It includes support for 15 ad networks (more coming soon) and Banners, Interstitials, Rewarded Videos. Plugin was released 2 years ago and was tested in many ways during this time. It’s stable, receives update every 1-2 months ,and we provide premium support.
If you have any questions, feel free to ask! 
Patrick,
gameDNA Ltd