Nighthawk R6700v2 Wifi Signal fails (light turns amber) but ethernet connection still working

I'm not really sure what's going on here. Primary problem: wifi signal fails and the light turns amber randomly.

History: ISP had an outage recently so some work was done in our neighborhood. Ever since then, my wifi signal fails and the light turns amber randomly. ISP detected that the modem had timeout errors, so they sent someone out to look at our cable wiring. They replaced some of our cabling equipment in the hosue that was 20ish years old. That seemed to solve the problem for a few days, but now it's back, and ISP says there aren't any modem problems on their end anymore.

Resetting the router doesn't solve it usually. In fact, the past few days it has been working most of the day until around 6:00PM but that might be an anomaly. Sometimes when I log into the management interface via ethernet connection, suddently the wifi signal starts broadcasting again? But I'd really not have to keep doing that since that's pretty inconvenient...

I usually hardwire when I'm working from home so I can verify that the ethernet connection continues to work well, so I don't think it's a modem/ISP-end problem. It's just the wifi signal that's failing on the router.

Anyone have any idea what's going on here?

(My firmware is up to date before anyone asks that. Yes I've rebooted my modem and router multiple times; the problem still persists).