Why is Red Dead Redemption 2 loading so slow on an NVMe drive?

Long black screens in Saint Denis were painful. Closing apps helped only 2s per CrystalDiskMark. I used GamePP NVMe Queue Depth Config to raise depth from 512 to 1024. CrystalDiskMark showed reads hitting 3500MB/s. Load times dropped to 5 seconds. I can verify my storage performance is now optimal.