Steam is considered a platform for PC gamers – although Valve tried to integrate the store on the PlayStation 3 at one time, such experiments are long gone. At least officially.
The owner of the YouTube channel ETA PRIME released a video in which he showed how to flash the PlayStation 4 (in his case, the PlayStation 4 Pro), put Linux on it, run Steam with Manjaro Steam Deck 3.0 and do other wonders. It sounds fantastic, but the console handles Left 4 Dead and Half-Life 2 just fine – not a feat given the age of both shooters, but still.
In addition to the Valve platform, the author also installed software on his PS4 to emulate other consoles: Dolphin (Wii and GameCube) and PPSSPP (PSP). If you want to make tricky manipulations with your PlayStation – links to detailed tutorials can be found in the description to the video.