So the consumer version of a consumer machine has user-replaceable RAM, but not the Pro version? Because "pros" have the money and people to have it done for them?!
Would they simply have realised, finally, that a 4k$ display is a bit too much to throw away when its computing component has become obsolete?
Only 8Gb on what can hardly be an entry-level model?
Did you run the iron on or above the chip, and at what temperature?