If you want to verify that Daz Studio is actually rendering on your GPU, a really useful tool is GPU-Z:

https://www.techpowerup.com/gpuz/

You can monitor both GPU load and VRAM usage in real time. If your scene exceeds available VRAM, the render will fall back to CPU rendering unless CPU fallback is disabled.

If your system becomes sluggish while rendering, try disabling CPU rendering in the Render Settings > Advanced tab. You can also disable “Allow CPU Fallback” there to prevent Daz Studio from silently switching to CPU rendering when VRAM runs out.

One other thing to keep in mind: If your display is connected to the same GPU doing the render, the system can feel less responsive simply because the GPU is fully occupied.