@yves_b you are correct they are connected over WiFi not ethernet. No, I don't use the 2.4GHz channel, a previous forumn mentioned that this could cause some latency so I switched completely to 5GHz....

I have WiFi mesh made up of one deco X50 at the start of the network which branches out to 3 Deco M5. I measured the bandwidth at each node and the bandwidth is halved after each hop X50 -> 600Mbps...