@Macca14 Check this link and scroll down to "Ethernet Ports" section: https://www.tp-link.com/en/home-networking/deco/deco-e4/#specifications It does not matter how fast wireless speed of Deco E4 is...

@Macca14 If you check hardware specs of Deco E4, you will see it has 100Mbps (Fast Ethernet) Ethernet ports, not gigabit. Main Deco E4 wired link is what limits Internet speeds.

@xavieru If you add third set, that would make it six Deco units in your Deco mesh. It should be OK. Up to 10 should be fine. I can't tell how well Deco mesh will work at your house, but Amazon has...

@Macca14 Deco model that you have, is it Deco E4?

@JMHCZ Main Deco M5 can provide much faster WiFi speeds than that, when everything is right. You haven't changed any configuration settings on Vodafone GigaCube 5G other than turning off its WiFi,...

@Brychance That actually tells there must be something wrong with Internet link, but as you don't trust Deco mesh anymore switching to a different brand makes sense. Three things I would recommend...