I think the legality of jailbreaking was actually decided by the Library of Congress DMCA exception process.
iFixit was part of that effort. https://motherboard.vice.com/en_us/article/8q89wb/how-to-fix... describes more about the company's history. I found it interesting.
https://es.ifixit.com/Answers/View/121003/The+replacement+ba... says (concerning a battery)
> The iPhone 4 Battery we sell is made to the same specifications as an Apple OEM part, but cannot be classified as 'OEM' because they are not made by Apple. Apple doesn't like to sell their OEM parts to anyone, so they are extremely hard to find. Our parts are brand new, fully tested, and made to the same quality as Apple OEM parts. They also come with a 6-month warranty."
The problem is, they are becoming less and less effective.
If you have no documentation or repair manuals, then it's harder to fix. An authorized repair site might know what error code 59276 means, but do you?
Apple famously started using a pentalobe screw, seemingly for the goal of making it harder for people who aren't at authorized service centers to carry out repairs. If a company uses non-standard parts when standard parts would work, this makes it harder for you to repair your own items.
In the pentalobe case, third-party vendors sprang up to sell the specialized screwdrivers, so it became less of a barrier. But imagine if the new screw were covered under patent that prevented substitutions .. and only authorized repair centers could buy the correct screwdriver.
Companies are using their rights under other laws to make it harder for you do to your own repairs. For example, farmers are turning to foreign hackers because farm equipment companies use the DMCA to prevent farmers from using anything other than authorized repair technicians from fixing the equipment. This equipment is increasingly reliant on DMCA-protectable software.
As you saw in this case in Norway, Apple wants to use its trademark power to prevent people from buying parts which would otherwise be legal
Are there any requirements would you force upon Apple in order to ensure that people have a reasonable ability "to repair any item they own or pay anyone else to do it?"
Make not mistake - it's also well-established law that the government can force companies to sell to people they might not otherwise want to sell to.
While you may have the right to do that yourself, they don't want you to have the right to hire someone else to do it for you.
They also don't want you to have the right to get those parts for your iPhone.
Apple goes after producers and technicians, and not so much end-users. For one, I think end-users have rights, like the first-sale doctrine, which makes it harder for Apple to do anything to you other than terminate your warranty coverage.
Though I think they really would have preferred if they could sue you for jailbreaking an iPhone - they lost that court case.