@David-TP Thanks for the response. There was some confusion in the description of my system. There is no ISP cable modem router. Here is the configuration: ISP cable feed -> Cable Modem -> ASUS...

My main Deco is connected (hardwired) in Access Mode to a router (operating in bridge mode and is there only to provide VPN), with three other Decos connected wirelessly to the main Deco. Smart DHCP...