Why does Lost Ark FPS drop after two hours of playing?

I couldn't stand the thermal scheduling; after two hours of combat, the CPU hit 92℃, causing my frame rate to tank from 100 to 60. I tried the motherboard's Enhanced Cooling mode, but the noise was deafening while the temperature only dropped by 3℃, which was infuriating. I used the GamePP Fan Curve Configuration to implement a steep linear growth between 70-90℃. AIDA64 FPU tests showed max temps suppressed to 76-82℃, HWiNFO confirmed stable temps at 72-77℃, and GamePP recorded fans at 1400-1600RPM.