Why does Kingdom Come II stutter when turning in Rattay market?

I felt totally ripped out of the experience when entering the Rattay town market; the screen tearing and stutters every time I turned my character were unbearable. I first tried closing every single background app in Windows, but it was a waste of time—my FPS only ticked up by 2 and loading actually slowed down. I then used the GamePP Resource Scheduler to set the game process to Realtime and capped redundant system services. In RTSS monitoring, frame times dropped from 22-45ms to 15-20ms, while AIDA64 showed available memory at 0.8-1.2GB and HWMonitor recorded 42-46℃.