Agreed it would be nice if there were official Apple support, but FYI there's a project called MoltenVK that implements the Vulkan API on top of Metal: https://arstechnica.com/gadgets/2018/02/vulkan-is-coming-to-...
https://twitter.com/Plagman2/status/1002324195135520768
https://www.phoronix.com/scan.php?page=news_item&px=Dota-2-I...
So that's pretty promising!