Idols (vocalists) that should get a vocal coach as soon as possible

I'm not hating, this is a thread where we discuss about the idols vocals because "we care about them and their voices"

So
Krystal (I love her but she needs some tips)
Tiffany so she can improve and be the next Beyoncé
Jessica so she can stop being an asthmatic squirrel to become a healthy squirrel

And
Basically every idol from YG who is not Lee Hi, especially if they're "main vocalists" and suck at it like those two