In response to all of this, AppLovin (the competitor to Ironsource) has launched an OpenSource project with the goal of creating as easy a migration as possible (via AI, asset migration script,etc.) away from Unity and to Godot, Unreal Engine or Cocos.
https://www.applovin.com/blog/migrating-from-unity-to-other-game-engines/
One thing intrigues me. Why engines use their own scripting languages (GDScript) and their own formats for assets ?
A specialized scripting language can be easier to integrate with the engine. In Godot case they even say that in the documentation (they said that the tried to use off the self scripting language first before going for a specialized one)
Also a specialized scripting language don't need to carry all the baggage off the self scripting language and can provide only what the engine's users need.
As a Godot game dev I love GDScript and I prefer it to for ex. C#. I use C# in my dayjob and I love the language but for Godot I only use GDScript.
Dropping UnrealScript was a big mistake. Unreal need a scripting language instead of forcing a choice between extremes (Blueprints vs C++).
I think Epic bought last year? a company implementing a scripting language for Unreal in order to integrate their language in Unreal but I haven't read any news lately about how the integration is progressing.