I recently got my custom game engine running on an M4 Macbook, and it was definitely a pain. Using MoltenVK to translate the API works, but there's a bunch of device features that are missing still I had to work around.

Off the top of my head it's missing drawIndirectCount, linePolygonMode, and the ability to set line thickness above 1 px, which are Vulkan 1.2 features. I also had to do some tweaking since several device limits are lower (can only reference ~500 textures at once instead of 64k like most systems)