Suggest you just store the stock router in the cupboard. Use deco alone. If not enough coverage, buy more deco nodes. Try to connect all via Ethernet backhaul. If can’t, wireless also ok. All will use single SSID.

Edit.

Modem = white device without antenna that must be retained.
Router = with antenna. Usually TPLink or Dlink. Can throw aside.

This post has been edited by deepan84: Aug 30 2021, 04:27 PM

Need to setting VLAN using UNIFI profile. Try to refer to this video. https://fb.watch/7JnjjJ4Rr-/