Unity's project quality settings provide preconfigured groups of settings that let you tune your app for different target platforms, managing the trade-offs between performance and rendering quality. Typically, for desktop platforms, you will go for high quality because it has the processing power. For mobile platforms, you'll favor speed at the expense of quality.

For other mobile platforms, the quality settings will most likely be tailored for lower performance processors and conservation of battery life. In particular, soft shadows and shadow cascades are too expensive to use on HoloLens and should be avoided. UWP builds may not have this setting by default. Change the Quality settings as follows:

1. Navigate to Edit | Project Settings | Quality.
2. In Inspector, you'll see a table with rows for different quality levels.
3. Find the column for Windows Store (Windows-icon).
4. At the bottom of the column, click on down-triangle and select Fastest for the default quality level, as shown here:

For more details and additional performance suggestions, see Microsoft's Performance recommendations for Unity at https://developer.microsoft.com/en-us/windows/mixed-reality/performance_recommendations_for_unity.