EmuDeck developer now has everything you need to build a Steam Machine with a $100 SBC
You can build your own EmuDeck Machine now.

EmuDeck is a certified legend among gaming handhelds, originally offering a quick way to configure emulators on the Steam Deck before becoming the de facto way to emulate on just about any handheld. Now, the developer is working on a side project under the name Playnix, and their first project is a custom Arch Linux image built around Steam's Gaming Mode, plus a handful of nostalgic covers built to project the ODRIOD-H4 single-board computer (SBC) — a $100 board that's capable of emulation most retro games at up to 1080p.