If you settle Winterhome and build the advanced generator there shouldn’t be a civil war
While this might seem impossible, if you choose to defeat the frost and are hyper efficient with steam cores (only deep drills, using the iron deposits instead of the wood, maxxing merit to skim off of only 1 deposit and take the 18 available steam cores in winterhome) it is possible to build the unlock the third generator upgrade
This should in theory solve the progress factions main issue which is upgrading the generator (and since you chose to defeat the frost it should be the progress version of the generator) while also giving a major concession to the adaptation faction in the form of Winterhome.
This should lead to a secret ending where both sides instantly reach some sort of understanding preventing the war from taking place. Maybe there should also be secret requirements like all neutral laws signed, minimum and maximum level of progress and adaptation and so on.