Newly installed Cox Panoramic - Wifi connectivity issues with laptop only

Upgraded to 100mbps Cox Panoramic on Thursday. Previously had 50mbps Cox with the Ubee DDW366. Zero issues. Had it for 18 months. Magically, I start having connectivity issues with my laptop after the Cox Panoramic is installed with their new Panoramic modem / router. Intermittently, it will lose internet connection. If I switch from the 5 ghz to 2.4 ghz or the other way around, it comes right back. If I use Windows to troubleshoot the issue, it comes up with "The default gateway is not available" and comes back online. Initially, though it might be that both the 2.4 and 5 were named the same as I just transferred the router name over. Changed both of the names, issue remains. From there, based on Google, I updated the network driver. No luck. I then uninstalled the network driver, reset the computer, and then had Windows find the newest driver and install it. Problem remains. After that, I reset all network related settings and restarted. Problem remains. All other devices are fine. Two iPhone X's, an iPad Mini, a desktop computer, and a smart TV are all connected via wifi and all fine. Main TV is connected directly to the modem and has not had any connection issues.

So this is clearly an issue with my laptop. Laptop was working this morning on old 50mbps before Cox arrived and installed new setup. I find it highly unlikely that wireless card decided to start having issues at this exact moment. Laptop is getting old. It's roughly 8 years old currently. Was state of the art when new, so it still does okay. That said, this thing has been connecting to wireless networks all over this country and in other countries for 8 years now without a single issue until Thursday. Windows indicates the wireless card is working fine. 

What's the deal? Anything else I should check? Is it possible it's still a fault with the new modem / router?