Dude...
Its actually quite clear. Listen up....
1. Vansh and Daadi are no team. Daadi told her the truth.
2. Vansh doesn't know that Riddhima has seen him shirtless.
3. He is not expecting to investigate him by looking at bullet mark.
So now what happens is, there was Indeed Vansh amd Vihaan. But he died that day at the cliff.
Didnt anyone noticed how vihaan changed his voice today when saying "jab bhi vansh ko khatra mehsus hota ho mujhe bhej deta". That got a hint. What could be more of a threat than Ragini getting kidnapped? The girl he was protecting from three years, the girl who holda his secrets. He sensed danger amd when Siya called her he immediately either sent Vihaan who later died. Or he made vihaan prepare and that throwing of stone was indeed an indicator. So either he died or his chapter ended for good.
Now vihaan needs to be real for daadi's story to be real. Because someone got shot and if vansh hasn't got any bullet mark them its vihaan that got shot. This guy in order to be vansh shouldn't have any bullet mark.
But....
If then fans theory is to be believed that daadi is involved then situation changes. But i highly doubt that. Firstly vansh will never share such heavy and drastic secrets with the most sensitive and kind hearted person of his family. Secondly getting a bullet is not a small incident. It could be easily confirmed all riddhu needs to do is to run either a google search or ask any family memeber or servant to cross check.... Maybe to not confirm but to get more information. Both vansh and daadi know about her spy nature. So it would be a foolish plan that can easil backfire.