weird lag problems on my new PC

[Trekkie]

So I got a new computer, got PR installed, it works, but I get DDOS level lag. I restart my cable modem & router, it's fine for awhile, then the lag starts again. Even just unplugging my network cable from the computer and plugging it back in seems to solve the problem. I don't even have to disconnect, I just unplug it for like ten seconds, plug it back in, I'm still in the game, and the lag is gone and my connection is good... for awhile. Maybe a minute, maybe an hour, but eventually the lag comes back.

I don't know whether this is a Windows 10 problem, an issue with my specific computer, or maybe something about the way my computer's connecting to the web vs the way my old one was, or what. Gotta sort this out quick because I got like a week and a half to get a refund on this PC if that's what I'm gonna do.

System Information
------------------
Operating System: Microsoft Windows 10 Home (10.0.19042)
Architecture: 64-bit
Current Culture: English (Canada)
Motherboard: Acer Nitro N50-600(DCH)
Processor: Intel(R) Core(TM) i5-9400F CPU @ 2.90GHz (Physical: 6, Logical: 6)
Memory: 8.00 GB
DIMM Modules: ChannelB-DIMM1: 8.00 GB @ 2666 MHz
Page File: 9.08 GB
.NET Framework: 4.6+ Release Build: 528372, Runtime: 4.0.30319.42000