Why does Frostpunk 2 stutter heavily when expanding my city in winter?

Rebuilding civilization in the frozen wasteland was a nightmare because the screen suffered severe stutters as my city grew. I first tried closing all background apps in Windows, but freeing 500MB of RAM was a drop in the bucket and didn't stop the lag. I finally accessed the GamePP Resource Scheduler to set memory priority to Highest and migrated the page file to 16GB on my NVMe SSD. RTSS monitoring showed the 1% low FPS rose from 15 to 32, and HWInfo64 confirmed memory temperatures remained stable at 40-48℃ with fans at 1200-1400RPM.