You mean PSOne (the slim) or the PS1? Because PSX is something completely different.
https://en.wikipedia.org/wiki/PSX_(digital_video_recorder) PSX was a recorder integrated with PS2.
Is that a joke about the lack of PS5 available on the market?
Back in 1995 everybody called the Playstation, few called it PSX before Playstation 2 was created then PSX name was dropped in favor of PS1 while the slim model is PS ONE, I was 7 years old in 1995.