Hi,
Unfortunately, Windows Sandbox does not support the use of dedicated graphics cards. It is designed to use the integrated graphics card of your computer. This is because Windows Sandbox is a lightweight virtual machine that is meant to be used for testing and running applications in a secure environment.
If you need to use a program that requires a dedicated graphics card, you may need to run it outside of Windows Sandbox on your host operating system. Alternatively, you could consider using a different virtualization solution that supports the use of dedicated graphics cards, such as Hyper-V virtual machines.