@JasperCat Keep Deco in Access Point mode. In that mode, your Xfinity router manages network (IP addresses allocations, and such), while Deco provides WiFi coverage. I have same setup in my house,...

@JasperCat See if this can help: https://www.xfinity.com/support/articles/hide-disable-in-home-wifi

@JasperCat Also updated another step for clarity: "Power on Main Deco. You should have it connected by Ethernet cable to Xfinity router."

@JasperCat I should have worded it better. I meant to say: "Disable WiFi on Xfinity router." No other changes are necessary on Xfinity, and do not change Xfinity to bridge mode. It will still be...

RomseyGuy wrote @Alexandre. The network optimisation has zero effect on 5Ghz side of things AFAICT @RomseyGuy My Deco WiFi 5GHz channel changed from 48 to 44 some time in last three months. WiFi...

@JasperCat If you have seen all three nodes online in Deco app and they have green LED, the rest should be easy. Power on Main Deco. You should have it connected by Ethernet cable to Xfinity router....