Wired network not connected

Hello, not sure whether this is Debian issue or KDE issue. I use Debian 12.

The wired connection stopped working a few days ago. I get my IP address from the router, however, no network is shown in Networks tab. When I disable wifi, wired connection icon with blue cable shows up.

It seems to be a DNS problem - I can ping IP addresses on the Internet.

Network card is working, I’ve checked it by dual booting.
A whole classroom of computers is connected to the same network without problem (with Debian 12 and KDE).
What could be the problem and what can I try to fix it?
Thank you.

Resolved: Changed NetworkManager config file to manage wired connection. Not sure why it stopped working at all…