@Tehya1
I got by with just one of the S1 factories for Ch11, but now I have 2. I also play through the chapters slowly, so that might impact how many you need. I don't remember at which chapter I needed the 2nd. I needed 2 each of the S2/S3 when I first started producing those goods. The good news was that I needed fewer of the T1/2/3 factories so that made some room. As I have gotten event bldgs, etc that make those regular goods, I've reduced my regular goods factories to zero for the most part. I have them in inventory and have put them out selectively if I started needing more of them. I'm a predominately fighting city, so I don't have the demand for goods in tourney/spire, either, so there's that.
My playstyle for building sentient factories: Over the course of the chapter I was 'in' I built the factories I'd need for the next chapter. I teleported them in and out as I needed their space for current stuff and worked on them when I could free up the space. Again, having the resources available to upgrade was less of a challenge since demands on my goods are so low.