I moved into a new place, bought Deco X50 Mesh routers, connected the main to my modem and then to a switch, connected that switch to another router acting as switch (cuz I didnt have another switch for reasons) and then just connected my second Deco.

Internet is fine, speed is perfect. The problem is packet drops on games. I connect via lan to second deco, and there's no loss at all. However, my friends also come to my place and we try playing together. The problem is they connect on wifi to the second deco (5ghz, 600+mbs easy speeds, sitting 1 foot away from router) but get like 30%-80% packet loss. I can't understand why? As soon as I give them a lan cable, it's all good for them.

I have already tried QOS in Deco app, added their systems as priority devices etc., but nothing helps. We can't all connect via ethernet cables unfortunately, so I am now thinking if this is a wifi device issue? Are there any settings that I need to check and configure to get a better packet rate? What am I missing I just can't get my head around this.