The game keeps crashing whenever I create or open a new world, regardless of whether I even set the world gen to cities

"The game crashed whilst starting integrated server
Error: com.google.gson.JsonSyntaxException: com.google.gson.stream.MalformedJsonException: Unterminated object at line 15 column 6 path $.swapper.
Exit Code: -1"

Creating new world without cities: crash-2022-06-13_20.24.31-client.txt
Opening old worlds: crash-2022-06-13_20.20.26-client.txt
Creating new world with cities: crash-2022-06-13_15.16.19-client.txt

This indicates an error in the json. Probably an asset that is configured wrong? What modifications were done to the assets?

absolutely no modifications to any of the assets or jsons of the mod

nevermind, apparently the json crash is coming from another mod