The original post is about as good as it gets for a side my side comparison. The results were fairly conclusive. Overheating issues,... tried several remedies.
The one that worked was the change of the water pump. The water restriction makes sense.

It is also good to know that this pump is sold by different vendors.

I feel better informed on potential issues and appreciate the heads up prior to making a purchase.
I am sure others will gain some value for diagnosing any problem they may have.