Just in case someone ends up here, I’ll answer my initial question:
This is the purpose of the PRIME Sync mode, as stated in the wiki:
In sync mode, rendering is completely delegated to the dGPU, while the iGPU only displays the rendered framebuffers copied from the dGPU.
Now, this is not working in my setup because I’m running Gnome on Wayland, which doesn’t seem to support the method employed by Sync mode which uses xrandr.
Moreover, in NVIDIA driver documentation, there is a specific Wayland known issues section which states the following about Wayland protocol/compositor limitations:
- Display multiplexers (muxes) are typically used in laptops with both integrated and discrete GPUs to provide a direct connection between the discrete GPU and the built-in display (internal mux) or an external display (external mux). On X11, the display mux can be automatically switched when a full-screen application is running on the discrete GPU, enabling enhanced display features and improved performance, but no Wayland compositors currently support this functionality.
Anyway, this issue resolution went further in another discussion. I’m also tracking it as an issue in my configuration repository.