how do i get edge to edge video on Iphone X?

I just tried it on a Youtube video and swiping out worked perfectly. Perhaps try deleting the Youtube app off your phone and redownload it. Also, you might want to simply reboot your phone.

Press and quickly release the volume up button

Press and quickly release the volume down button

Press and hold the power button until the Apple Logo appears, then let go

Your phone will restart and you won't lose any data or settings

Actually, do the reverse of pinch. With 2 fingers move them outward to expand to full screen.

Great. I'm glad it worked for you.