Why does my character lag in dark dungeons with Fanxiang S790?

I was stuck in a dark dungeon, and my character moved like they were in molasses. The Fanxiang S790 2TB PCIe 4.0 NVMe M.2 SSD was hitting 95% queue depth utilization, causing severe read latency. I tried increasing virtual memory first, but it did nothing to fix the stutter. Frustrated, I opened GamePP NVMe Queue Depth Config. I increased the queue depth from 1024 to 2048 and enabled forced write cache. The difference was instant. CrystalDiskMark showed speeds jumping to 7000-7200MB/s. HWiNFO64 confirmed the drive stayed cool at 42-45℃.