Why does Marvel Rivals drop from 160 to 80 FPS during fights?

I was devastated when my immersion broke during hero duels; the sudden drop from 160 to 80 FPS whenever particle effects peaked was jarring. I tried setting power management to maximum performance in the driver panel, but it just made my fans spin wildly at 1800 RPM per HWMonitor without fixing the stutter. Then, I used the GamePP Resource Scheduler to set the game process to Realtime priority and suppressed background services. RTSS confirmed frame times converged to 6-9ms, while GPU-Z showed a stable 2.6-2.7GHz core frequency and AIDA64 recorded 68-74℃.