Yeah, it makes no sense. The standard is OpenGL, Vulkan, but Apple ditches it just to be different or something. At least some big game engines support it, e.g. OGRE, so if you do want cross-platform dev, it's possible.
But like USB-C, at some point you should just embrace the industry standard.
Also, there's Vulkan on Metal, but there's translation overhead, and I have no idea what other issues it causes. Dolphin emulator did some research on that.
Game consoles don't do Khronos APIs for the most part, they are really only standard on GNU/Linux and Android, really.