Windows periodically loses the network - almost every minute - how to treat?

Question

Windows

Motherboard Gigabyte h61m-s2 flashed bios F9 i3-3240 processor
Windows 10 installed Corporate LTSC
Network card is defined as Realtek PCIe GBE Family Controller
The driver was previously 2016, I updated it to 2021 - it did not help.
It started unexpectedly this morning. Sinned on the provider - no, other hosts on the network are working fine.
The patchcord switched from the switch directly to the router. Router - Asus RT-N11P

Who can advise what?

PS I wanted to install another network card, but only PCI is available.
And on the specified motherboard, there is only one PCIe x16 slot (for a video card) and two PCIe x1 slots
, that is, another network card also needs to be purchased separately.
.

Answer 1

First, replace the cable, no?

that is, another setevukha also needs to be purchased separately.

You can stir up UsbToLan

Answer 2

test network stability after booting Windows from LiveCD/DVD/USB flash