Why does Dead Space 2 Remake drop from 75 to 20 FPS?

Entering the ship's interior was a disaster; my FPS would plummet from 75 to 20 per MSI Afterburner. I tried lowering graphics to Low, but while VRAM usage dropped, the I/O bottleneck stayed exactly the same, which was just infuriating. I used GamePP NVMe Queue Depth Configuration to set the read queue to 128 and optimized the write cache policy. Random read performance rose by 12% per CrystalDiskMark, and HWMonitor showed temps dropping to 48-55℃ after I tuned my fans.