I think it's the same problem with this post, these also coincide with the time frame
I thought it was the lack of fans on the netduma router, so I bought fans with usb rubber mounts, to put under the router, and I must say that now it is much faster in computing.
unfortunately that was not the problem.
Restarting the router does not solve the problem, the router continues to behave by restarting the LAN and WAN network devices without ever stabilising.
Procedure to definitively solve the problem
1) remove the rj45 wan cable and wait 60 seconds or wait for the wifi and lan lights to be solid again
2) deactivate and restart the ethernet card of the pc
3) reconnect the rj45 wan cable