I have purchased the Deco P9 on Amazon and for the last week have been having a nightmare with thes units

I have a new house with Cat6 cabling to key areas in the house, all installed professionally and tested.

my setup is a fibre connection with the router provided by digiweb in Ireland it is a Fritzbox 7530. I also have a new Tp- link 24 port switch connected.

All these units are upstairs in my office

the master unit is connected directly to the router,

I followed all the instructions to the letter multiple times and finally got the one in my downstairs hall connected with cat6 cable( although when looking at the app it doesn't appear to say Ethernet, port is working fine)

the second slave is in my kitchen/ sun room on ground floor, same as 1st slave. The slave connects to the one in the hall as its source, and the hall connects to the office as its source.

the second slave refuses to work and load on Ethernet, its ok on WiFi, however both downstairs units go off line from time to time and come back a few minutes later according to the app. When offline I still get full signal, and get approx 50 mbps of a service of 150 meg, upstairs it tests anytime at 140 mbps,

I am ready to throw these in the bin unless anyone can help,

have been on chat 4 times but unfortunately I have more knowledge than the support people and I have only about a week with these devices can anybody please help