So, basically, if Apple implement "security features" to prevent non-Apple parts working, repair shops would not be allowed to disable those features, and would have to use Apple parts, at whatever excessive price Apple charge?
Sigh. I figured someone would call that requirement evil without looking at the whole picture.
Note that Apple actually left the door open for non-original parts, provided the user is told about it, but this is about something different - you're dealing with a chain of trust issue for the Apple security model.
This first became apparent when non-Apple installed fingerprint sensor replacements didn't work: those devices had to be integrated into the chain of trust as it exists in an iPhone and 3rd parties were not able to do this, IMHO wisely because installing parts that did not actually do the job would then become rather easy - and guess who would then get the blame? Apple, of course.
Replacing a screen or a digitiser? Absolutely, should be easy, provided there's some measure of control the repair doesn't void the waterproofing. Battery? Umm, problem. Not the waterproofing, but the quality. If you have ever seen a lithium battery ignite you know you don't want that near someone's head or in someone's pocket, but who can Johnny End User trust to stick the RIGHT battery in there and not some cheap knockoff that will eventually blow up?
And again, if that happens, the repairer won't get the blame but Apple - front page headlines will be about an iPhone blowing up, with weeks later a small print report on page 9 that the cause was an non-certified OEM battery. Yes, it could have been made a lot cheaper, but would you get on a plane if you knew that the person next to you had a dodgy battery in his device? Remember, you can't extinguish the thing. Dell already had that problem, and those were their OWN, QA verified batteries.
If you apply some logical thinking to the issue you'll see that the 'right to repair' people and politicians tend to skip over trivial problems like safety and maintaining security because those don't fit into their narrative. The truth, as always, lies somewhere in the middle. Apple is not blame free here, but there are some possible some sound reasons for their reluctance.