@Huw53 This usually happens when device uses "randomized MAC address." On each of such devices you'll need to configure "use device MAC address" for Deco mesh SSID.

@Nathanpgonzalez Those I can recall are for a different issue: you must be running Deco in Access Point mode, use "Test Internet Speed" button in Deco app. That "Test Internet Speed" will report...

@Nathanpgonzalez One more thing just came to mind. On both iPhone and computer open web site and note Public IP address it reports. It should be the same IP address when web site is opened on both...

@Nathanpgonzalez Everything seems to be OK. Your PC connects at WiFi6 speeds. Your Main Deco must have negotiated gigabit wired speed with modem/router - if it were 100Mbps, that would be the max...

@Nathanpgonzalez One more thing: what app or web site do you use to run speed test on your phone?

@JohnR117 The first M5 you configured will be Main Deco. Main Deco must be connected to your router by Ethernet cable. All other M5s are Satellite Deco - they can connect wirelessly to Main Deco.