Picture-in-picture mode is coming to iOS 14 (soon-ish?), but when it does, it probably won’t be available for the one video app you likely use more than any other: YouTube. That will change soon, too—YouTube is rolling out support for picture-in-picture mode right now—but odds are good that you aren’t going to be able…
source https://lifehacker.com/you-can-unlock-youtubes-picture-in-picture-mode-in-ios1-1844880329