PoE 2 using only 4.5gb of VRAM. I have a 6GB GPU

My specs: i5-9400, GTX 1660 6GB, 1TB nVME SSD

I'm using the in-game tools to test my PC performance. I have checked the meter multiple times and it shows PoE 2 using maximum 4.5GB of VRAM. But my graphics card has 6GB of VRAM. How can I use more of my GPU's available VRAM?

Why would you want to?

Even if it was possible to force the client to load textures irrelevant to whichever zone your character is presently in, doing so could not possibly improve your performance in any way. In fact, doing so would be highly likely to worsen your framerate. There is literally no reason to want to do this.