I own the M9 plus with the main unit in my basement and hardwired units on opposite ends of the first floor.  I have a lot of devices in the basement I would like to hardwire, XBox, Roku, Receiver, TV, etc.  Is the order below the proper inline placement for the switch?

Modem -> Main Router -> Switch -> Mesh units, Xbox, Roku and other devices?

Is there any downside to having a switch with these units?

Thanks