AC1600 - connectivity lags on main PC

en my wife & I started working from home full-time a few months ago, we upgraded from our previous Netgear modem router to the AC1600. (Comcast had also boosted our speed recently so the old model wasn't fast enough to keep up.) I have the router connected to my personal PC, with a second Ethernet cable running from the router to my work PC. Everything else that is using the signal (wife's work laptop, phones, etc) is on Wi-Fi.

Oddly, every 1-2 days, the Internet speed on my personal PC slows down/lags. Some webpages seem to take a while to load or sputter to fully load. The way I can tell for sure if it's slow is if I stream my favorite online station. If it drops after a minute or so, I know the router's acting up again. All I have to do is reboot the router and it's fine again. But it shouldn't really be happening at all. My work computer connection is always fine, Wi-Fi is still Wi-Fi so it's not going to be 100% perfect all the time regardless but it's certainly improved over the previous router.

This wasn't an issue with our old router and only started when we upgraded to the AC1600. I tried swapping around all the different Ethernet cables to both PCs as well as switching the (identical) Ethernet cable that came with the new router instead of leaving the old one plugged in. We've twisted the coaxial cable as tight as we can on the back of the router too.

Any thoughts out there as to a cause and/or solution?

Thanks!