Packet loss on Ethernet port (en0) only

Hello! I have a really strange problem with my network:

I see a lot of packet loss only in en0 interface, about 10% - 30% and disrupts my work (remote desktop connections, NAS etc).

The issue appears only on that interface.

No problems when pinging:

• between other hosts and all of the gateways.
• from iMac's virtual interfaces / VLANs (802.11Q) to all of the gateways.
• from the Recovery mode.
• from VMWare Fusion guests binded to the VLAN interfaces.

VMWare guest binded on en0 interface I may get much smaller packet loss.

From the above I believe it's clear that the issue in the operating system.

It's an iMac (Retina 4K, 21.5", 2019) with Monterey 12.3.1.

I had Little Snitch installed but its removal made no difference.

In the Console I don't see anything related to networking...

Any ideas?

Thank you