Hi
Chiron is in the conjunction Sun-Venus-Chiron.
I'm interested about this subject, because I have the same : Sun-Venus-Chiron conjunction in 11th house (but in Virgo).
I don't see it like a stellium. We can say you have a Stellium in Capricorn (because you have 4 placements so it give you a strong Cap energy.)
But there is no stellium in 12th house.
Mercury doesn't belong to any conjunction (maximal orb for this aspect is 10 to 12°)
Sun and Venus aren't rulers of the houses that deals with work in your chart. (like 10th for carreer, 6th job, and 2nd for money)
So, I don't know if you can use them for a choice of carreer. Maybe. This is just my point of view and other people can bring another insight on this question
However, it's the Sun so it's important in general