Extract GPU usage percentage on Apple Silicon M-series Mac in Xcode (graphics card monitoring with Swift)

I'm working on an app for macOS where it would be very useful to display the GPU (graphics card) workload usage as a percentage. CPU usage monitoring is easy, but GPU monitoring on Apple Silicon is next-to-impossible. Apple only seems to give us our app’s GPU usage which is not what we want, since we want to total GPU workload for the whole system. I'm using the latest version of Xcode and Swift, any ideas how to achieve this?