Valve's SteamOS 3.7.3 Preview improves support for Asus and Lenovo handhelds

After Valve announced in January that a public beta of Steam Deck's SteamOS is coming for more handhelds, the initial SteamOS 3.7 Preview added the start of it and now the latest SteamOS 3.7.3 Preview brings more improvements for other handhelds.