Very granularly: simple tools like the Windows Task Manager Performance tab's Ethernet Throughput graph can provide enough of a clue that a network connection is suffering.
There are many utilities that show this info in useful form in the system tray; perhaps some would be able to superimpose it on top of the video conferencing software (like OnTopReplica).
I often have such OS-level tooling open during VC chats, but it's not natural to have to keep an eye on another tool, especially when you want the "last seen"/latency figure nearly instantaneously so you know the context for lack of signal (human vs machine).
There are many utilities that show this info in useful form in the system tray; perhaps some would be able to superimpose it on top of the video conferencing software (like OnTopReplica).