Found the solution: Copy the "Il2CppOutputProject" folder from the folder in which unity compiles when you click build, to the folder /Users/YourUserName/Library/Developer/Xcode/DerivedData/Unity-iPhone-blscvbr2hfyidpbrutzxrjqmreah/Build/Intermediates.noindex/ArchiveIntermediates/Unity-iPhone/IntermediateBuildFilesPath/Unity-iPhone.build/Release-iphoneos/artifacts/arm64/buildstate/ (the path in the error) For whatever reason, Xcode is searching in this path for it. I'm not a Mac expert, I'm only forced to use Mac to compile for the iOS store, so I have no idea where to fix it properly. Why is iOS and Mac always such a gigantic mess?!? Android and Steam takes 3min to deploy and here it's just one issue after the other -.-

I have exactly the same problem. Have not found a solution. Xcode 16.3 Unity 2023.1.20f1. Worked under Xcode 15 and also Unity 2023.1.20f1. My conclusion for now is that it's an Xcode problem since Unity version did not change and deployment was successful under Xcode 15.