Good news for NVIDIA GPU owners on Linux, as an NVIDIA developer has confirmed that work is in progress to get Gamescope working with their drivers.
Gamescope, for those not aware, is a Wayland compositor originally forked from the older SteamOS 2 compositor. It's a big part of what makes Gaming Mode on the Steam Deck do all it can. This includes features like scaling, AMD FSR, frame rate limiting and more. It would be great to see it fully working across more vendors, especially for those gaming on multiple monitors as it can help get around some troubles there too.
However, it only really works with AMD / Intel GPUs (Mesa) right now but that is set to change. On the NVIDIA forum, developer amrits confirmed "We are working with Valve to ensure Gamescope runs well on our driver." and linked to a GitHub request to fix up issues with it to have it work on the NVIDIA driver.