Xiaomi phones support it in all regions. Think about it, a company famous for putting ads in system apps has the feature but "privacy conscious" Apple literally put in extra work to disable it everywhere it's not legally required.
> I also found out the Chinese version has the ability to block an app for accessing both mobile data and Wifi/WLAN data.
Yet Apple is choosing not to enable it for everyone. It seems like it would be an easy and obvious privacy win, no?