The problem I have is whether to choose Android Studio or Visual Studio? I have to develop a simple app for a school project that can work on both iPhone and Android.
The most important factors for me are Android and iOS compatibility. Although note that i would like to become a Software Engineer when i finish my course. (I'd like to work for Apple, just saying!)
After that id like easy integration for Google Ads and such if i do develop another app that people actually use to support development. (I'd also like to stick with one easy programming language that's compatible with a wide variety of platforms since i'm a beginner and have only ever used Pascal)
First of all - Android Studio and Visual Studio are IDE's. Tools to create code. What you are asking is programming framework. I assume that when you are talking about Android Studio you mean Native Android Development and by Visual Studio you mean Xamarin.
If you want to create crossplatform app then Native Android Development is NOT a way to go. Xamarin might work for you, BUT - you'd rather recommend you to go with Flutter. It's much more performant than Xamarin, programming model is friendlier for developer and technology seems just more refined. It's also officially supported by google, so no worries about support.