Steam Machine inherits a major flaw from the Steam Deck: anti-cheat systems remain incompatible with Linux.
Many popular multiplayer titles fail to launch on the device because of this restriction. Owners cannot play hits such as Fortnite and Destiny 2 despite the hardware having plenty of power.
Not all online games suffer from these limitations. Many run without issues, and some developers explicitly adapt their games for SteamOS. Halo: The Master Chief Collection serves as one example, allowing access to campaigns and modes that do not require active anti-cheat software.
You can bypass these restrictions by installing Windows as a primary OS or through a dual-boot setup. This approach allows access to problematic games and services like PC Game Pass. However, the workaround sacrifices the seamless experience of SteamOS and may negatively affect overall performance and optimization.
Source: iXBT.games