Per Valve's patch notes released for the Steam OS 3.6.9 Beta update for Steam Deck, dubbed Megafixer, an interesting oddity has been added to SteamOS' input functionality. While most of the Megafixer update's patch notes are indeed related to bug fixes for Steam Deck (particularly external display errors, OS corruption issues, and other such glitches), one specific update made to SteamOS' Input layer is the addition of "Added support for extra ROG Ally keys".
Since SteamOS 3.6.9 isn't even available on Asus ROG Ally, this seems particularly odd — until you remember Valve actually did make publicized comments vowing to give SteamOS 3 a public release before Steam Deck launched, and has simply remained silent on the matter since. In the interim, projects like HoloISO and Bazzite have emerged to give users of other handheld gaming PCs and desktop/laptop owners, in general, the ability to closely imitate SteamOS 3 and its core features.
So, does the existence of HoloISO and Bazzite perhaps override the need for a public SteamOS 3 release? Absolutely not — besides the documented fact that Valve already intended to create a public SteamOS 3 release, it's still painfully apparent that HoloISO and Bazzite aren't quite providing the polish and stability we could expect from an officially maintained public branch of SteamOS 3.
HoloISO outright does not support Nvidia GPUs and is missing native features of SteamOS 3 like on-the-fly TDP and clock speed controls, with Decky Loader required to partially restore that functionality. Bazzite seems to be in better condition overall and even comes with lots of extra bundled software — and even a Deck-native version — but still requires Decky Loader and BIOS settings changes for on-the-fly TDP controls with per-game profiles to be made possible off of Steam Deck. This is one of the best features of the Deck and SteamOS 3, so it's a real shame no current SteamOS 3 alternatives can actually do it without modification.
Besides, these latest patch notes and pre-Deck release comments by Valve, we've actually heard a more recent comment on SteamOS 3 coming to devices outside the Steam Deck. Comments made to PC Gamer by Valve employee Lawrence Yang in November 2023 indicate that SteamOS 3 will target other handheld gaming PCs first, and then branch to "more arbitrary devices", meaning other laptops and desktops.
