After playing Horizon Zero Dawn for four hours, my WD Black SN850 2TB gets read/write latency that causes scene transition drops. Should I clear the cache?

After roaming the wilds for a few hours, scenes that used to load instantly started hitting 2-3 second white screens—absolutely maddening. Monitoring showed the WD Black SN850 2TB random read/write latency creeping up from 0.04ms to 0.11-0.17ms (GamePP), a textbook case of cache fragmentation killing I/O efficiency. I first tried the built-in Windows disk defrag, but doing that to an SSD is useless and just adds wear—I can't believe I even tried that. Instead, I used the GamePP Resource Scheduler Panel to set an automatic NVMe cache flush every two hours and locked the game's I/O priority to 'Highest'.