I really do not want everything to be made of the Pathogen, the Pathogen makes Aliens through Facehuggers and Alien like things without biomechanical aspects just by itself. That's more than enough, it's just getting ridiculous if the Engineers also use it to grow technology and augment themselves.
I have no issue with them doing that on principle, but just leave the Eitr, or Pathogen, or Accelerant out of it.