Much of the Windows mixed-reality platform depends on Unity. However, that’s not always the best option for many reasons, especially its licensing model that’s still very focused on the games market. There are alternatives. You could use WebXR in an embedded browser or work with the cross-platform tools in the Power Platform that’s built around Babylon.js’s React Native implementation. But if you’re working with .NET code and want to extend it into augmented reality and virtual reality, you still need a set of .NET mixed-reality libraries.