com.apple.security.cs.disable-library-validation (allows loading the Steamworks SDK library and overlay library)
com.apple.security.cs.allow-dyld-environment-variables (enables the overlay library to be injected into the game process)
I think you already do the second but am unsure about the first
I just read an interesting piece of documentation on Steam - https://partner.steamgames.com/doc/store/application/platforms
It specifically requires that...
com.apple.security.cs.disable-library-validation (allows loading the Steamworks SDK library and overlay library) com.apple.security.cs.allow-dyld-environment-variables (enables the overlay library to be injected into the game process)
I think you already do the second but am unsure about the first