I have FTTP high speed internet into Telstra Modem

Deco XE75 PRO main router feeding TPlink switch to two more Deco XE 75's via ethernet

I have set up a home office without ethernet and the Wifi signal struggles with multiple devices during periods of peak neighborhood use .

Can I add a DEco WPA 8631P (or other model) WiFi adapter with its wifi disabled and connect my Deco into it via ethernet ?

i am effectively using the adapter to replace an ethernet cable .

I have tried moving the deco on a long Cat 6 cable strung through the house and when its in the office everything flies 

does the adapter work? is there a better solution?

appreciate your help and HNY to all