@AxelSSS
Your Test-NetConnection results are revealing:
Google = 29 ms
Cloudfare = 11 ms
Tomorrow's test results could be reversed.....
I am not sure about the meaning of "a real drop in ping would be around 12-10 ms".
Your expections perhaps being Google at 17 ms and Cloudfare at 1 ms or <1 ms.
To fully and (hopefully) properly gather more data you would need to run many more tests and work on understanding what the results may or may not be revealing. That is exactly what I am trying to do.
However, the thread's discussion has shifted into expectations, drivers, and updates.
Once there has been some resolution regarding the bad Ethernet cables and drivers etc. there may or may not be some need for additional testing.
You are in good hands with respect to those matters.
Test-NetConnection becoming just another diagnostic tool in the toolbox to keep in mind.