Graphics Vram selection tiers

the maximum seen in Fedora is 2gb that is too low please raise to 4gb 8gb 16gb 32gb and in 16gb increments to 256gb
there are now 288gb gpus

 

Parallels VRAM is only used as a framebuffer. So this parameter only matters if you need to cover several external displays.
The VM then uses Metal or OpenGL APIs, and these calls can access the whole GPU memory.