@TP-Link That is correct. However, if I use supplied EE router instead of the Deco, I get the full 300 on wireless. Why is the Deco performing so poorly, in comparison?

I'm on EE Fibre Max 2 I get 300 Mb wired and using the Deco app speed test but can't get above 210 on any wireless device, even right next to the main M5. I get 300 if I use the EE router It's not a...