Hi, im planning a setup as seen above. I would like to confirm if i cant connect deco s7 through tl-sg108e switch to my ax72 router and setup so that my router and mesh device will have same wifi network. 

my home only has single fiber cable that is situated in a corner (main) room, so modem is there. at first i put my router in my game room which is exactly in opposite corner and get a long cat6 cable to carry connection. my pcs, servers etc could get gigabit lan connection just like how my wifi devices in game room get healthy wireless connection. but i couldnt get my wifi signal to main room which has a smart tv and a couple of smart home devices. i dont want to use modems wifi since its not in my router network. so i come up with a plan in which i keep my modem and router in main room, router will provide wireless connection to that room and neighbouring rooms, then via cat6 cable ive put between game room and main room before ill connect my router to tl-sg108e switch which will provide cable connection to devices in game room. then ill connect a deco s7 mesh to switch via cable so that that mesh device would provide wireless connection to wireless required devices in game room and also neighbouring rooms by using same credentials as router and basicly i would have a mesh wifi system that covers my whole home.

what i cant be sure of is if mesh device would accomplish required connection to the router via cable (cable-switch-cable) then distribute it as wifi? 

if you have any other suggestions i would like listen.