no lie the simplest fix is to just unplug the egr valve for free. Wild how that works. I did all that work to get mine working fully again.. and I don't even need to pass emissions. lol
Oh well, when the government takes over more in the coming years and forces emissions testing down our throat at the point i will pass.
TL/DR though: EGR passageways to cylinder clog in order of longest from valve and the car doesn't know. So it eventually pings the head gasket to death in each cylinder. Usually head gasket in cylinder 1 goes first and then you need to do the gasket. Completely avoidable though. My ass felt it 20k miles ago when the car was pinging incessantly and the car had no misfire code.