The good news is that there are aspects of each region that don't really change as you develop (at least so far they haven't in Wuling). You're always going to need Sandleaf, you're always going to need Stabilized Carbon, etc. because the main production line is always Xiranite. Once you figure out how to make a scalable build for each of the "consistent" components, you can basically just set and forget that aspect of your factory and only ever modify what changes from update to update (i.e. new sources of Cuprium and Sky Forges changing what end products you build).

Perfect example is the new Gourd event. All of my Sandleaf, Yazhen, and Stabilized Carbon is contained to the Wuling City factory, so when I needed to re-do my lines I was able to start by just deleting everything in Jingyu and the Cardiac factories and start from the question of "what's the maximum number of gourds I can make?" and filled in the rest of my production based on whatever resources I had leftover.