Ok doing this has made a massive difference. I am able to switch off the ping hack.
The only energy-saving option on my Intel hardware was the MIMO Power Saving Mode, I switched this to "No SMPS" and the connection is now stable. It had defaulted to "Auto SMPS".
What I don't understand is why it suddenly started behaving badly after 10 months of stability. It has to be the recent Windows 11 update??