Why is The Sims 5 sluggish when building large communities?

Switching between build and live modes felt sluggish, with a subtle lag that made the whole interface feel unresponsive. I first tried disabling all unnecessary startup items in Windows, but response speed only improved by 1%, which made me incredibly anxious. I then used the GamePP Resource Scheduler to expand virtual memory from 16GB to 24GB and set the process priority to High. Frame generation time dropped from 15-30ms to 10-14ms per RTSS, and HWMonitor showed a stable 40-46℃.