Thank you for the reply!
Turns out I was wrong with my presumption that when building a native library in Android Studio you don’t need the .jar file. After adding the .jar file as a library the function returned the number 1 i.e FMOD_OK.
For anyone with the same problem. Just add the .jar file in the lib folder of the application. Right click on it and select Add as library and chose to add it to your Android module/library.
No calling of the org.fmod.FMOD.init was needed!