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
The first controller looked the same, but was very good to use once you got used to it. The build quality, though, was…fucking terrible.
I had to fix my controllers so many times that in the end I was swapping them out almost weekly. Still, felt great in the hand.
It might be you just got unlucky. Mine is still going strong all this years, and I use it often.