Some of Apple’s support for SpriteKit is spotty. Their scene editor had a major issue in Xcode 11. Didn’t get fixed until iOS 14 came out. ios - Does Xcode 11.2 scene editor allow adding components? - Stack Overflow
One advantage over Unity is you aren’t fighting bugs on two platforms. The assumption that if you can just get things working well on iOS with Unity you’ll get Android for free doesn’t really apply.