How to stop FPS swings in crowded areas of Kuro no Kiseki?

Walking through bustling city areas, my frame rate felt like a roller coaster, dropping from 60 to 25, which was absolutely maddening. I first tried setting the fan to full speed in BIOS, but the noise was like a hairdryer in my ear and temperature only dropped to 83℃. I used the GamePP Fan Curve Configuration to change the 65-85℃ gradient to a step-up increase and set 90℃ as the full-speed trigger. Core temperature stabilized at 79-84℃ per AIDA64, FPS converged to 48-58 per RTSS, and memory stayed at 58-63℃ per RTSS.