Phoronix article: https://www.phoronix.com/news/Steam-Machines-Frame-2026
Also listed here: https://store.steampowered.com/sale/hardware
Valve has already sent support for the new Steam Controller upstream: https://www.phoronix.com/news/New-Steam-Controller-SDL
That is the complete opposite of what they are. They are notorious for supporting all the hardware they have released indefinitely. They still keep releasing updates for the steam link and steam controller to this day and both of those have long been out of sale.
I mean officially the steam controller updates were discontinued in 2023 for the internal configurator and everything like that any current updates or anything like that is either the third party or being hacked together by people using it.