For several years I use the Archer C7 in combination with the Deco M5. The Deco M5 is used in Access Point modus. 

I have several devices, such as NAS by cable connected to the Archer C7. All wifi devices are connected to the Deco M5.

De Deco M5 or the newe BE25  is not (cannot) be connected by cable for backhaul.

The system is now slowing down due to more devices such as TV-sets with wifi internet. So I consider to buy the Deco BE25 to replace the Deco M5.

What is the best way to use the Deco BE25 in this configuration. Use the Router modus or should I set the BE25 in Acces Point modus, just as the Deco M5 is now?

I'll be happy to get some advice.