DVR not functioning after an installation of an ARRIS Gateway with no coax required

I was sent this Gateway to replace a Gateway that I was told did not support my ATT Signal booster. It arrived and I installed it plugging cable into the correct ethernet port and the network and broadband. The internet worked my hue hub and security camera worked so I assumed it was good to go, packed up the old one, and returned it.

Later we turned on the FireTV and could not get UVerse to work. Checked networks setting and the network was connected.

Every time I restarted the received I got a "not available at this time - please restart receiver. I went through more than an hour of offsite support and requested US support - got to the point of reinstalling software on the UVERSE box and the connection dropped!! Finally got them again but not a good agent - asked for someone else and after complying with everything the agent ask I was transfers to Mostafa - the most arrogant (Edited per community guidelines) I have ever talked to - I was an IT VP for 15 years and this man should be fired. He refused to listen when I was trying to ask if this was a problem in the gateway config and told me I had a wiring problem and would be charged if I wanted a tech to come out! He said I needed a gateway with Coax and he was ordering one - could not tell me what it was, when it would be here and I do not see it in the orders. Has someone dealt with an issue like this? Did I mention I had to add $10 to my swear jar!

There cannot be that many choices in Gateways and this should not be this hard!