There are many difficult achievements in "Ice Age 2", and the Isolationist is one of them. To achieve this achievement, you only need to complete the game without collecting any resources from the frozen wasteland or colony. , it is very difficult to complete the game without resources.
How to get the Isolationist achievement in Frostpunk 2
Isolationist
Complete the game without collecting any resources from the Frozen Wastes or Colonies
Complete a playthrough without collecting any resources from Cold Outposts, Settlement or Colonies.
Choose a large, resource-rich map and play on Citizen difficulty. Obviously, the Colonial Coldlands ambition is incompatible with this trophy.