you may have faulty units. however i am not a big fan of plume that is the company that makes the xfi pods and you can go to the store and buy them comcast just rebranded them. in terms of mesh imho i would look at eero.
you say you have a wide home not tall? you may be able to get away with one eero and a beacon or two. but get ready for the price of these they are not cheap but thry will do all kinds of magic to make sure you are getting as much speed as you can.
We have a wide ranch style home. Our xb6 was installed on the east side in the bedroom closest to the drop. We’ve never been able to receive a signal in the master bedroom on the west side of the house. I upgraded to xFi advantage last month and received the 3 pack of pods on Friday. While we now have coverage in the master bedroom and are achieving about 40 mbps in that room, areas which used to receive around 300 mbps are now only receiving between 70 and 80. The only time we receive 300+ is when the device is connecting to the gateway directly. For one example, in the living room the iPad is now plugged into the wall next to the couch. This is the closest pod to the gateway and previously was a spot that would receive around 300. Now when I sit on the couch, the iPad is connecting through the pod but the speed is about 75. All 3 pods are connected to the gateway according to the app. I know the pods are not supposed to improve bandwidth just coverage but why are they degrading performance in areas that used to receive the bandwidth I’m subscribed to when the device is connected through the pod and how can this be fixed?
I didn't like the xFi Pods specs, so I spent some money and got the Orbi with two satellites. I have a consistent wifi signal everywher in my home now.