Many thanks Andruser for your kind reply below. I set QoS on the Deco app for my iPhone 12 Pro Max, and set limits of max 400Mbps download, 50Mbps upload and still no good to see the speeds beyond 200Mbps and that also varies depending on how far I am from P9. Even when next to the main P9 acting as a router (I forgot to mention that I set VM Hub3 to modem mode, and Deco main P9 as the router) still no good. I guess your good advice on WiFI 6 tri-band system might be the way forward. I do have another issue, however, whereby my garden office is at the far end of my garden and I need internet in the office and also in the garden. I was contemplating getting an outdoor WiFi access point such as TP-Link EAP225 Outdoor AC1200 to connect to the internet in the garden, and the office in the garden. This might not be the best solution in my case. As you suggested I wonder if I go for a WiFi 6 tri-band 3 unit system, have 2 of them in the house, and third one with ethernet cable from home to the garden office, would this let me have internet in the garden as well? Or would I be better off on the top of that to install outdoor access point as well if I need to have internet in the garden too?
Many thanks in advance for your kind help.