Hi there community

I’ve got a simple set up with three M9plus Deco units. The main unit connects directly to the cable TV modem, then other two are linked to it by an Ethernet connection I had installed afterwards (ie it doesn’t really take advantage of the mesh capability any more). I need to get an additional unit to improve coverage onto the garden (it won't be mounted outdoors), which could either be connected by mesh or Ethernet. Which model from the current models would be the best purchase for a single extra unit? The M9 Plus is difficult to source as a single unit as it isn't in stock / available at my usual websites.  I’m happy with the current setup aside from the coverage issue. Ideally the replacement has the same or better specs than the M9.  Thanks!