I want to use tp-link deco axe5400 (axe75) pro with ATT fiber gateway

I'd like to set up better wifi using the deco axe5400 pro with my fiber att gateway.

I'm asking what is the best method to have the highest speeds?

Ideally I'd like to turn off the att wifi part of their router and use a cat 7 cable from the att modem/router to my deco router. Then use additional deco routers for a mesh system for my home wifi network. I do not have any cat cables run through the house, so it will be all wireless except for the first deco set up with the gateway using cat 7. 

Will my system work? 

What setting do I need to change when I log in to the gateway IP address?

Any insight or help is greatly appreciated! I only have a modest functional understanding of these things but am willing to learn!