Why does Pacific Drive stutter when entering new regions on SN770?

I was driving through anomalous zones when every new map block caused a 200ms micro-freeze, totally killing my immersion. I tried closing all background updates in Windows, but the stuttering barely changed, leaving me stuck. I then opened GamePP NVMe Queue Depth Configuration, increased the queue depth from 32 to 128, and synced the write cache flush policy. After this, frame times converged to 12-16ms per RTSS, and the drive stayed at 42-52℃ per AIDA64, while random reads hit 30-50MB/s via GamePP Hardware Sensor.