Most of what I read says there is not any phosphorus on Venus, which I take to mean none in the atmosphere or none detected. I mean, it gets hit by iron-nickel meteorites and probably has some apatite in the crust.

There are $CO\_2$ soluble phosphorus compounds, like $PH\_3$, which could be leached out of rocks by the near supercritical lower atmosphere moved around and redeposited.

I am just throwing some thinking at it; what do you, people in the know, know?