Is it possible to override the main Unity object

I would like to see the there’s a main class file I can override to put in my own custom code, much like Prism does in Xamarin Forms “App : PrismApplication”

Is this possible? I saw there’s a unity start up method that’s fired and was hoping I could find a Hook to add some customizations.

I see I can do that at Scene load, but I’d like to do that before scene load.

I have no idea what you mean by “the main Unity object.”

Perhaps you should point to some documentation, and also mention which runtime platform you are targeting. Each one would be a completely different app-facing “object,” whatever is contextually appropriate for that platform.

Here is what is used for scene load: Unity - Scripting API: RuntimeInitializeOnLoadMethodAttribute
but I am looking to hook into before the scene is loaded as more of a global means to only incur one load.

I’m trying to target iOS platform, but after looking through the documentation I don’t see how to hook into the main object as I described im my question referring to Xamarin as an example above.

At build time it would probably be in the default language that Unity is written in, not a native type as it is pre-compiled anyways. So I would assume the platform is irrelevant.

From what I see is this: unity - How do I know when the app is launched, loses focus and gets focus again on mobile? - Game Development Stack Exchange

But it seems like a Scene template and extending the SceneManagerAPI is probably better. Wish there was a central object to override that unity uses even if I have to mess with .h header files, but it looks like it’s all structs.

I see that also DryIoc is pretty easy to embed, but I see wish I could grab on to Unity Start and start loading. Probably just always run the init scene, but that is so hodge-podge