TL;DR: Proton, a compatibility layer for Windows PC games to run on Linux, is being developed by Valve. Valve's Linux-based SteamOS is used on the Steam Deck gaming handheld and gaming PCs.
Proton is the compatibility layer for Windows PC games to run on Linux, and Valve is leading its development. Valve's Linux-based SteamOS can be found on the popular Steam Deck gaming handheld and gaming PCs that want the freedom and customization of Linux - and none of that Windows bloat.
A Steam Deck with GeForce RTX hardware? It's not outside the realm of possibility, thanks to Valve's latest Linux update.
Valve has recently released a Proton Experimental update that fixes numerous bugs and performance issues while adding support for NVIDIA's DLSS 3 technology, which includes NVIDIA's Optical Flow API that enables DLSS 3 Frame Generation to run on modern GeForce RTX 40 Series graphics cards.
This update doesn't mean Valve will release Steam Deck 2 with an NVIDIA APU, but it certainly paves the way for precisely that. It finally lets GeForce RTX 40 Series owners running Linux enable Frame Generation, if nothing else.
However, with rumors that NVIDIA is looking to release its first Arm-based APU with GeForce RTX graphics in 2025 - a chip that will deliver up to GeForce RTX 4070 laptop levels of performance - Valve could be eyeing such a chip for the upcoming Steam Deck 2.
Valve's engineers have previously confirmed that they're working on the Steam Deck 2 but are waiting for a generation leap in performance before releasing a follow-up to the current handheld. GeForce RTX 4070 laptop performance would deliver the generational leap in performance that Valve is looking for. However, price and efficiency (it also needs to maintain the 15W target of the current Steam Deck's AMD APU) would also need to be factored in.
Alternatively, an NVIDIA APU with GeForce RTX graphics could be integrated into a Mini Steam PC running SteamOS or a handheld from another hardware company looking to create something new - with full DLSS 3 support.
Perhaps NVIDIA will create its own gaming handheld and choose SteamOS as the operating system; who knows? SteamOS's significant benefit is that it's optimized for handhelds and efficiency, so it feels more like a console like the Nintendo Switch than a gaming PC or laptop. Also, games can run faster on Linux with less stuttering and other issues.