The following guide may help free up VRAM so that it doesn't run out and cause stuttering issues.
System tested: Ryzen 3600, RX 5700XT 8GB, 16GB RAM
Optimisations done by the AMD driver may have caused VRAM overload, which forced data to be stored in RAM and Harddisk, both significantly slower than VRAM.
By disabling any optimisation done by the driver, VRAM usage is reduced to ~5GB on highest settings@1080p.
Run the game and open the AMD performance overlay to check GPU VRAM utilisation. If it reaches your GPU's max VRAM (8GB in my case), the game will stutter and there is a high chance this guide will solve the issue.
Open the AMD driver software and
1) turn off all the settings you can possibly turn off (i.e. morphological filtering, surface format optimisation, OpenGL triple buffering)
2) use application settings for Anti-aliasing and Anisotropic filtering
3) override application settings for tessellation mode and turn off maximum tessellation level.