

Not an expert, but I’ll give it a shot. That way someone will speak up to correct me. 🐸
With an AMD GPU on Linux, you’ve got your kernel amdgpu
driver which talks to the hardware, loads firmware, etc.
Sitting on top of that is Mesa, which provides an opengl and vulkan driver. Your application talks to the opengl driver which talks to the kernel driver which talks to the hardware.
Windows has it’s own graphics stack, which has video card drivers and DirectX drivers.
Metal is Apple’s proprietary Vulkan knock-off, which seems to exist to force game devs to write games that only run on MacOS. This hasn’t really worked.
Magma seems to be about inserting a layer between the kernel driver and Mesa, so you can use Mesa OpenGL drivers on top of Magma on Windows kernel drivers? That’s not really something most people are looking to do.
They do seem to alternate between making MacOS graphics worse and wondering why nobody’s making games for MacOS.
Management seem to think that desktop Mac has the same market share that iPhone does and keep wondering why throwing their weight around isn’t working.