So you just installed linux and looking to test your gpu.

Vulkan

at frist install vulkan-tools.

To test vulkan run vkcube if you see the cube then vulkan is working.

Opengl

Just run glxinfo | grep "OpenGL renderer".

Laptops

You midge have seen that distros no longer ship with prime-run.

Don’t worry you can reinstall it.

sudo nano /bin/prime-run

#!/bin/bash
export __NV_PRIME_RENDER_OFFLOAD=1
export __GLX_VENDOR_LIBRARY_NAME=nvidia
export __VK_LAYER_NV_optimus=NVIDIA_only
export VK_ICD_FILENAMES=/usr/share/vulkan/icd.d/nvidia_icd.json
exec "$@"

sudo chmod +x /bin/prime-run

now use it like prime-run vkcube or prime-run glxinfo | grep "OpenGL renderer".