Consent is only one legal basis, but it’d be hard to argue that sharing their data for processing by Apple is legitimate interest, and the other non-consent bases don’t apply here.
No worries here, Apple IRP actually requires independent business to get a waiver signed by the customer. Among other things Customer acknowledges repair has no warranty from Apple, despite repair being performed "using original Apple parts by Apple Certified technician working within Apple authorized independent repair program"!
Why Apple should know that a random Joe replaced the touchscreen of his iPhone?
I don't see any reason. HP doesn't know I replaced my keyboard three months ago and the keyboard works.