I've been using the same setup for a couple years with the exception of a few upgrades here and there to my CPU and such, and had no issues with packet loss or jitter at all. Starting 2 days ago, my internet suddenly has up to 90% packet loss and up to about 500ms jitter with ping spikes up to the thousands. I am on ethernet with my router and my modem literally about 1 foot from my PC. I am using the built-in ethernet controller on my MSI B450-A motherboard, with a Ryzen 5 5600X, a 3060Ti FE, 32 gigs of Vengeance LPX at 3000MHz, and a Linksys EA6350 router. I have tried restarting both the router and modem, my PC, unplugging/replugging all of the ethernet cables, and nothing has worked so far. Should I buy a new router or a network card to try and fix this or is there something I can do to actually pinpoint the issue?