Over various forum and by experience we see gnome desktop multi seat option does not works with NVIDIA Desktop GPUs at all but works with Nvidia Server GPUs.
We in our testing also found that where gnome multiseat option does not works with NVIDIA Desktop GPUs , other gdms works fine with Nvidia Desktop GPUs and support multiseat options.
Can others share their experience on gnome and Nvidia Desktop GPUs in context of multi seat usage ?