Once you buy and download it through iTunes, you can use a DRM removal tool like TunesKit, and then you’ll have a workable m4v file to do with as you please.
Tuneskit no longer works. It also DEFINITELY never worked with 4k.
What DOES work?
On iTunes? Nothing, AFAIK. There’s no way around their DRM.
not even HD Content Using TunesKit?