Apple has explicitly made replacement parts non-user-servicable at this point. It's called "serialization" and prevents even OEM parts (like a screen from a different iPhone) from being recognized by the phone. [1] This is the type of consumer un-friendly behavior that R2R seeks to defend against.

[1] https://www.ifixit.com/News/45921/is-this-the-end-of-the-rep...