So I spend a little bit of time looking at it and I don’t think it’s related to Apple Silicon but to Version 5.1.
My best guess is that Lyra Starter Game was build way before UE5 was release and now in version 5.1 they are cleaning up the source code and a lot of the code Lyra was build on its been deprecated.
/Engine/Source/Runtime/Core/Public/Misc/CoreMiscDefines.h:232:43: note: expanded from macro 'UE_DEPRECATED'
#define UE_DEPRECATED(Version, Message) [[deprecated(Message " Please update your code to the new API before upgrading to the next release, otherwise your project will no longer compile.")]]
Engine/Source/Runtime/CoreUObject/Public/AssetRegistry/AssetData.h:109:2: note: 'AssetClass' has been explicitly marked deprecated here
UE_DEPRECATED(5.1, "Class names are now represented by path names. Please use AssetClassPath.")
They will have to update Lyra code again for 5.1