Yeah, the terminology can be confusing, partly because there are just so many options.
What “prime-select” currently lets you do is choose between two configurations:
- iGPU-only mode. Everything is rendered on the AMD or Intel integrated GPU. The NVIDIA discrete GPU is not used.
- "display offload" mode. Everything is rendered on the NVIDIA dGPU and copied over to the iGPU for display.
What the new “GPU screen” thing allows is a third mode:
- "render offload" mode. Everything is displayed on the iGPU. Everything is also rendered on the iGPU except for specific ("offloaded") applications.
It sounds like you’re currently using iGPU-only mode, where everything including your games are rendered on the AMD Raven Ridge GPU. If you want to run things on the NVIDIA GPU you’ll need to configure one of the offload modes described above.