Hi! Read about your playthrough in the other thread and I'm sorry that it got ruined by biters. There was a scenario, but it was removed, as it was buggy (surfaces therefore resources didn't connect). Rather, I introduced a map generation preset that removes biters completely.
Do you have a save where the factory is not destroyed? If you send it to me, I can put borders around your factory (set map width + height to just enough) and remove biters + pollution, which can also improve performance.