Bullshit - what “research”? Apple is in no way comparable to goddamn Google and Facebook here. Their ad sector is pretty much “display my app in the AppStore search if they search for similar things” and things like that, that only uses the actual search term, and very basic stuff about the user. They can make relatively much money on that, because they artificially own the whole “Apple market”, so they don’t have any competition there. They don’t fingerprint you across the whole internet, that’s for sure.
It’s as much a “harm they put in place themselves” as website cookies are - these are technical artifacts that were maliciously used. It is just not arguing in good faith to claim they made it for tracking purposes - it’s like basic software development practice to create some unique IDs, and it has plenty useful roles.