@Max92253 

To get a replacement you would contact our support team to do the needed troubleshooting. Once they determine it is bad, they can then begin the replacement process.

Yes, you can swap the main Deco node with one of the other units to see if that would help.

In the meantime, I would focus on the one node, have the others powered down. If you get slow speeds with the single node, swap the Ethernet cable it is using and port. If it is still slow, look at your settings. Remove any device on high priority, disable Fast Roaming, go into QoS (see if the internet speed is set the correct amount). The QoS should have a setting for "standard" among others like gaming or chat, if it does select that.

Going back to the Ethernet cable, even if it already is new or what came with the Deco still swap that out.