cant say i can help much on wifi... i have herd it can be spotty a few posts on xbox direct forum suggest a min and max space between the router and xb1. others have mentioned how the router is setup and how "new" it is and the avaliable speed it can push..
most will say you want it wired for speed... wifi tends to have dips and such in upload/download and will be noticable in most gaming situations. i can even say going wired you may see those high/low speed drops.
i run a gaming router that was a mid/top of the line router few years back.. i had to upgrade from a normal because it just could not keep up with the xb1 in my area. i do have dsl (not commercial) but the basic package.
did they direct you to do a soft reset (holding xbox button for 20 seconds) on console
you can do a netowrk reset. power off router and all that.. turn power off on xb1 for 1 min.(unplug)
you can go into settings netowrk, advanced, alternative mac addy, reset it.. it will restart the xb1 but when it restarts it will reset the wifi and netowrk all together..
unfortunatly i cant say if any or all will work.. but i can say if its an issue odds are it wont go away you will learn what ones work for you over others. i get issues from time to time and recently with anamous and lizard squad its not a netowrk issue but a ddos shut down of xbox servers all together.. one of those things you need to have multiple ways of checking with microsoft to see what services are down.
