It really looks like your Deco X10 might not be behaving normally. With a 250 Mbps line and a Hub 5 in modem mode you should easily see close to full speed on the main Deco when testing via a wired connection. Getting only around 25 Mbps usually means something is wrong in the setup or the unit itself. Try these checks so you can confirm where the bottleneck is coming from: Test the main Deco with a wired device connected directly to its LAN port. If the wired speed is also stuck around 25 Mbps the problem is definitely not Wi-Fi but the main Deco node or its WAN negotiation. On the Deco app, open Internet Connection settings and check that the WAN port is negotiated at 1 Gbps. If it shows 100 Mbps or keeps dropping to 10/100 this will explain the slow results and usually indicates a cable fault or a faulty WAN port. Make sure the Deco is the first device after the Hub, with a good CAT5e or CAT6 cable. If possible try another Ethernet cable and another port on the Hub. If the wired test is fine but Wi-Fi is still around 25 Mbps, check whether the phone or laptop is connecting on 2.4 GHz instead of 5 GHz. Sometimes devices fall back to 2.4 GHz if the signal isn’t strong or if the node is stuck in a bad state. A restart of all Deco nodes often clears this. The constant drops of your Tapo plugs also point to instability. They usually disconnect only when the 2.4 GHz band is unstable or overloaded, which again is not normal for a new system. If the wired speed on the main Deco is bad even after cable changes and reboot, then the unit is very likely faulty. At that point the support team should be able to confirm replacement because no configuration issue would limit a Deco X10 to 25 Mbps on a 250 Mbps modem-mode connection. Let us know what your wired test to the main Deco shows - that’s the key to confirming whether the device is defective