(To begin, I would like to clarify I know SteamOS 3 is not out, and may not be for some time. This is a feature request regarding a portion of this distribution providing upscaling and game performance benefits.)
As many may know, SteamOS 3 is coming soon. A key piece of this is its compositing window manager known as gamescope.
https://github.com/Plagman/gamescope
As of now, the Nvidia proprietary drivers lack some features required to make this work. To quote the Github page,
Can support NVIDIA if/when they support atomic KMS + accelerated Xwayland + Vulkan DMA-BUF extensions.
Blockquote
The open source community drivers currently suffer from performance problems that could impact gameplay performance. Adding this functionality to the official driver would allow for equivalent/greater graphical performance in gameplay to Windows.
On a side note, I would also like to see DLSS 2 support.
Thanks for your consideration.