Apple's SDK doesn't contain a game engine.
2D => https://developer.apple.com/spritekit/
3D => https://developer.apple.com/scenekit/
Alongside lots of other game related goodies, https://developer.apple.com/games/
Second, who would adopt a platform specific "game engine" like scenekit? Are you going to rebuild your whole game to port it, is that the plan here? Apple is categorically unable to compete with actual game engines exactly because they dig their own hole, invent their own proprietary closed technologies (metal, scenekit) up & down the stack. They aren't playing keep up with the real tools, a game of "me too": they can't begin to compete with the real deal even if they tried.
Surely you must be joking?
Apple engines are so bad that Cocos2D-x is basically a copy of their features, using C++ instead of Objective-C/Swift, one of the engines that Google and Microsoft give first class on their platform SDKs.
Not every game engine needs to be a bullet point list copy of Unreal capabilities.
And no I am not joking, contrary to many here, I had a past life in demoscene, been a former IGDA member, previous GDCE attendee (London and Cologne), have been inside a couple of known AAA publishers and have kept my contacts from them.