Steam is an application that can execute a variety of games and even software, which can even execute Windows applications without the need of Wine via the Steam tool Proton. This can can be a replacement for Wine although some applications might not work as expected. Most games are built for Windows but most work just fine via Proton and Proton works both on regular Linux distributions, including LFS without all the setup required for Wine.
As Steam is a gaming application, it depends on many tools, libraries, and graphics APIs to function and perform as it should. Obvious among such software would be OpenGL, Vulkan, and graphics drivers. Less obvious software includes audio and a window manager or desktop environment.
Please check Steam Dependencies to find what you will need before proceeding, although most of Shared Dependencies is a straight shot. There is some choice involved such as choosing if you want X11 or Wayland, Alsa or Pulseaudio, so forth.