I have an Orbi RBKE962

I have had both Xbox One, now a XB1 X and a series X. Any of these models have never seen much over 400-500Mpbs on any of my NG routers, Orbi or Nighthawk. Xbox wireless have never been on the bleeding edge of wifi and have only been or seems to be designed with the average general wifi specs. Since the wifi is AC on game consoles, and probably limited to 80Mhz channel width, this will be limiting to wifi speed performances so you'll never see anything near 900mpbs or beyond with these wifi radios in the game consoles. And honestly, gaming and gaming traffic isn't a major bandwdith hog anymore. Most all gaming just needs maybe 500Mpbs on the down and 50Mpbs on the up. 50Mpbs works well for me and I'm one of two games in the home. 

If you want to see better speeds and performances on any game console, use ethernet connections. Will always out perform wifi. 

Good Luck.