New Orbi RBR750 - multiple issues

We just purchased a new Orbi BRB750 (Firmware: V3.2.16.6_1.4.4) wifi-mesh system a few weeks ago. At first, it seemed great, there was no more complaining from the family about the poor wifi signal of my AT&T modem, Pace 5268c (1Gb fiber). Shortly after, though, My oldest started complaining about his games. he was unable to play is primary game, Eve Online. He sat on phone support with them for hours before even telling me. When he was launching his game the game updates would not download and eventually time out. He found he had the same issue with Steam. Funny enough, when I launched Eve from my identically built computer, it launched fine. He insisted it was the network, I instisted it was his OS. He went as far as completely wiping his computer, putting on a fresh copy of Windows 10 and tried to download, install and update Eve...no dice, it just timed out when he launched the game and update it. I started looking at the Orbi network, even did a full factory reset and set it all up again, I could not get his client to work. Eventually I turned off the Armor protection and he was able to update the game, but it took 15 minutes to launch, and actions in the game was lagging so bad he could not do anything. As a last ditch effort, I unplugged his ethernet cable from the Orbi and plugged into the AT&T modem. Now he is on a completely different network (a 192.168.1.x) instead of what we are on (10.0.0.x).

I thought our propblems were over, then I noticed some dismill transfer rates on my machine. I found that my NIC was set at 100Mbs instead of a 1000Mbs. I restarted my machine and it was back at a Gig. Now, it seems, that every time I reboot, it is like a toss of the dice, will I get a Gig, or just 100Mbs? This is annoying as hell, but I dont reboot often.

Now, last night, my youngest is having the same issue as my oldests, but with his new COD game and the (I think) Blizzard launcher, he just times out.

Has this type of behavior been seen before? or did I just waste $600?