I'm not sure I understand. The game is available on other platforms, but that's not what your post's title is asking, specifically mentioning 'on PS5'. Or were you trying to point something else out that I'm not awake enough to see yet?
For what it's worth, I've not heard of it on Steam, either, but I effectively work two jobs right now so I don't have much time to game, sadly, and don't often keep up with the news.
If I had a nickel for every time in the past week I saw an article about a courier game I'd have two nickels. Which isn't much, but it's odd that it happened twice.