Back in 2005 I finished my Masters thesis. For that thesis, each chapter was it's own file. The master document was essentially an outline where each chapter was a link to an external Word file.
With all the data and equations in each chapter this was an absolute life saver. I could work on a chapter without the 15 min loading and the constant bogging down of having to re-paginate every time I typed 3 words.
Anytime I wanted to see the whole doc at once I could load up the master doc. Obviously, I had to do this for the final draft.
That was then, 12 yrs later I don't remember how I did it and it probably wouldn't matter if I could given the UI changes since then.
All my Googling led to people suggesting that you insert Object as Text... But then the formatting gets screwed up. I haven't yet tested it but it appears to be static rather than a link.
Does anyone know how to do this in Word today?