Why does WoW freeze for 0.8s in cities with a WD SN850 1TB?

I was losing my mind in Valiras; every time I tried to turn in a quest, the screen would just freeze for 0.8s. It totally killed the immersion. I tried disabling write caching in system properties, but that was a disaster—my loading bar just stuck at 99% indefinitely. Finally, I used GamePP NVMe Queue Depth Configuration to force the queue depth from 32 to 128. After this, CrystalDiskMark showed 4K random reads jumped to 76-88 MB/s, while AIDA64 measured read latency peaks dropping from 115-142ms. HWMonitor confirmed temps stayed at 56-63℃.