U-Verse - Arris Gateway - Still Losing Signal After Multiple Technician Visits

We have had fiber installed for about a month. Since then, we have had 4 separate technician visits to our home to attempt to resolve issues we're having with fiber cutting out, and taking minutes to reset with the reset button. This happens MULTIPLE times a day, and no technician really has any idea of why. When they come out, they perform some tests, but since nothing fails, they don't know what's causing it. This is INCREDIBLY frustrating, as I have 2 children who need to have consistent access for school work, along with the rest of the house. When the fiber cuts out, it also disconnects the WAN box, which then has to be re-paired with the receiver in our bedroom.

Here's what's been changed each visit:

1. Some network tests on their iPad, but not modifications to equipment
2. A new WAN box was installed. Tech measured voltage going back over ethernet to the Arris, and decided that the WAN was causing interference.
3. Tech could wiggle the cord coming from the fiber box to the Arris, and signal would cut out. Decided that since it was a cheap press fitting, something must be coming loose and causing issues.
4. Tech felt a small kink in the fiber line, and cut it out/corrected the fitting.

We have an Orbi mesh system, and have the onboard Wi-Fi turned off. Also, we currently have the router set in passthrough with its own unique DHCP pool (192.168.48.*), which we got from a Reddit post here.

We never had a single issue like this on Spectrum. I would like for someone to help point me in the right direction of a real solution, because I'm almost about to throw in the towel with AT&T.

Model Number of Modem

Home Network Status

 

Passthrough Info

Statistics