Why does my Sapphire RX 590 stutter in Enshrouded build mode?

I was losing my mind in Enshrouded's build phase; the Sapphire RX 590 GME 8G VRAM hit 95%, causing 25ms frame times. I tried increasing the page file, which dropped FPS to 45. I used GamePP DLSS/FSR Calibrator, switching to Balanced and setting sharpening to 70. RTSS showed frame time dropping to 15-18ms. AIDA64 confirmed GPU temp at 68-74°C. The immersion is back.