Why is my Cox Gigabit Service CRAWLING???

Thanks again guys. Here's another update. After taking the actions below, I've come to the conclusion that I have probably dealing with more than one problem, but the one causing the most pain is, as you suspected, the physical layout of my network. I think I've been expecting WAY too much out of the mesh system. Although I only have a 1900 sq ft townhouse and try to cover it with five mesh pucks, the primary router is all the way at one end of the house. Nowhere near line of sight and certainly not within 10 feet of each other. 

So this week I am changing my layout. I'm moving the Cox coax from the office to a location in the primary living quarters. There are 12' ceilings and a very open floorplan. The modem and primary router will reside on a ledge about 9' from the floor and have line of sight to two of the three TVs we use as well as three of the four wifi pucks. I've ordered a 100' run of Cat 6 ethernet cable to run back to the office for my desktop. 

Now for the action I took:

* I connected my desktop directly to the modem via a new 24" Cat 5e cable and booted in safe mode. I ran the speed test and speeds jumped from 250 to nearly 500! Encouraged by that, I did a system refresh and reinstalled Windows 10. Probably a good thing to do, but it didn't yield any further improvement.

* I went through the house using the Google Home app to see which point devices were actually connecting as suggested. This was an issue. Many/most of my devices were connecting to points which were clearly not the nearest to them. Some of this may have been caused by me troubleshooting. I was taking points on and off line a lot and devices may have connected to a distant point when the closer points were off line... and then they just didn't change their connection when the entire network came back up. But that was only a part of the problem because I'm still seeing them make odd connections. I'll just keep an eye on it and see if the problem fixes itself when the new layout is in place and stable. At this point though, I have gone to each device and forced it to connect to the closest point.

* I brought all four points into the office with the main router and brought them on line. I felt this would ensure they were operating in a spoke and hub arrangement. Then, using first my phone and then my Chromebook, I forced connection to each puck in turn and ran speed tests (speedtest.net). My phone saw download speeds consistently in the 300 to 450 range... although my Chromebook reported somewhat slower speeds they were still near 200. My five mesh points are a mix of newer and older. I did not run this testing using ethernet backhaul connections. Firmware on each of the pucks is current. The primary router continued to report seeing ~850 mps from the modem.

So at this point I'm optimistic that I'll be able to reconfigure things into a much more functional solution. We'll see what kind of speeds I see once things are stable, but a couple of mysteries remain at this point.

     * Why is my desktop only seeing 500 mps (at best) when connected directly to the modem using a short Cat 5e cable?

     * Even when in the same room, my points only seemed to provide speeds of <450 mps. I will run a couple of tests using backhaul connections on the three pucks which accept it to see what happens but I haven't done that yet. 

Thanks again and I will report back once everything is together.

Rick