Playtron are quietly building up their Linux-based PlaytronOS behind the scenes, and not only have they released their first Alpha but they've pulled in another investor too.
Additionally, the first Alpha version of PlaytronOS has now been released for those of you who wish to test and give feedback. So far they note it has been tested across the AYANEO 2, ASUS ROG Ally, GPD Win 4 (2023), Lenovo Legion Go, Valve Steam Deck LCD and Valve Steam Deck OLED.
Quite a nice list of tested handhelds.