Well after a bunch of messing around. I discovered what the problem has been for me - the extruder drive gear!!

My original Flashforge included this iron extruder stepper gear:


However prints would keep jamming, and I couldn't even print with Ninjaflex due to jammed extruders. TPU was better, but not by much.

Then I discovered my brand new Flashforge had a different style Aluminum extruder drive gear (similar to this picture, but silver color)





As soon as I swapped drive gears, my printer worked flawlessly. I can print Ninjaflex perfectly!!!! Phew!

Thanks for the Help JimC