You might have a network loop. If the network loops eventually a packet will come along and circulate forever filling up the network with traffic. For example your PC could be connecting to both Ethernet and Wireless and bridging could be enabled on the PC.
Described here:-
https://www.windowscentral.com/how-s...ion-windows-10
To get help on something like this you will really need to provide a network diagram and details of the equipment models in use. I have attached a sample diagram - NOT directly related to your network. A home router (usually) contains three separate traffic passsing functions and it can be critical to recognise that when troubleshooting these issues.
