Besides Valve funding FEX-Emu for x86_64 binaries to run on AArch64 Linux as part of their Steam Play (Proton) efforts in being able to get Windows x86/x64 games running on AArch64 SteamOS for the Snapdragon-powered Steam Frame, there is also work happening in kernel-space to help this emulated gaming experience on AArch64.
André Almeida of consulting firm Igalia, which has been longtime partners with Valve on their Linux engineering efforts, presented at the Linux Plumbers Conference last weekend on enhancing the Linux kernel's Futex interfaces for helping ARM64 with an emphasis on a better emulated gaming experience. Igalia has also been helping Valve with the open-source graphics support for the Steam Frame, the color management pipeline / HDR initiatives, and other efforts like crash data collection on the Steam Deck.