the most impact is PROTON_HIDE_NVIDIA_GPU, it prevent major of vertices explode but it still occur but less than normal launch that vertices explode entire screen and unable to play game thus, problem come form nvidia GPU driver.

by disable nvidia gpu util by PROTON_HIDE_NVIDIA_GPU vertices explode ruduce significantly, include all launch options game stable in long run without performance degrade.

if, GPU has only 8GB vram but you have a iGPU consider enable it and move other task that not steam(Typical Desktop Environment done it automatically ex. KDE) game to ram help to prove vram overflow in Medium texture setting.