You are completely on point with not being interesting in this "Right To Repair" rhetoric that I can only assume Apple is using as a marketing gimmick.
From when I first started fixing Mac's - which I only ever replaced parts, Apple would never allow you to take a soldering iron to their godly products - they at least had a lot of parts you could replace. Displays could be replaced on Macbooks from the 2007 era for example and you could buy those displays in bulk for a reasonable price.
From the unibody/clamshell era, 2010 onwards, Apple made these machines barely repairable, displays are now industrially glued into their metal housing, almost all I/O is soldered to the logic board requiring a full replacement to fix, good luck if you're out of warranty.
In exchange for the faulty part back, Apple will offer an authorized provider about 20-30% discount on the part which they call an "Exchange Price". Nothing hurt my soul more then to have to quote customers $700-900 AUD (exchange price) to fix a simple backlight malfunction.
Interestingly the price of replacing a Display or a Logic Board through Apple's 'Exchange' program is the same cost price for a Service Provider and these are the most costly parts of a Mac.
They do not offer exchange prices to these independent providers and the 'stock' price of Apple's service parts are astronomical.
I highly doubt that any independent repairer has ever ordered any part from Apple. Maybe they ordered tools, Apple does have some decent tools.