Gamestreaming at 4k from 21:9

So I'm having a pretty frustrating issue and I'll try to explain as best I can.

I have a Acer x34 monitor+1080ti on my pc end.

I have a 55 inch Vizio p55 4k tv on the other end.

I've yet to find a way to gamestream a game, like Ori and the Blind Forest and stream it to the tv at 4k resolution. I'm only able to select up to 2560x1440p

I've seen numerous references online to people gamestreaming at 4k from a 21:9 monitor but none really go into detail how.

I have "allow experimental features" selected as mentioned by everyone.

I've tried both with DSR "dynamic screen resolution" on and off.

I can manully set 4k in the gamestream options on the shield and see it in the game options but it will not apply.

Anyone have any ideas or are doing what I'm trying to accomplish? I do not have the Creator's Update installed for win 10, I believe it's version 1703?