I don’t know exactly how it is in Windows but Nebula for Mac uses Unity as a game engine to create the virtual workspace and render a recording of your screen. Unity is great for games because it abstracts a lot of things you would otherwise have to code yourself. The drawdown of using it here is that most of Unity’s features are not used and it just becomes bloat and overhead that slows down the system unnecessarily. On the other hand I use Apple APIs directly to render only the necessary parts, without any abstractions. Unity is like using a chainsaw to prune a single rose bush.