Metal supports multiple optimizations that you can use to increase the performance of your application.
Metal supports memoryless render targets which enables you to render to a RenderTexture without backing it up in system memory. Unity only stores the contents temporarily in the on-tile memory during rendering.
Metal supports memoryless render targets on mobile devices from iOS 10.0, tvOS 10.0, visionOS 1.0, and on desktop devices (including Apple silicon) from macOS 11.