Oof ok so I have a couple of answers but one of them is CL from 2NE1. I mean she went running into a building during an earthquake to get Dara. I don't think any leader can top that act for me if I'm being honest. It was so clear how much she loves and supports her members. Not to mention I love that she never gave a fuck what people said about her.
Another would be Suho from EXO. He started out having a group of 12 members he co-lead with and then to have that other leader leave, meaning he was left to take care of a large group on his own suddenly and NOT to mention after finding out about the departure he accepted an award by himself while the members processed and cried behind the scenes. He's dorky, but deserving fo respect. I mean he also protected EXO when some fan was trying to get info or some shit on a chat room. He shut that shit down, and gave no fucks. He also showed INCREDIBLE displeasure publically to inappropriate behaviors (Like that awful sign at the one concert). I mean he lost so many members along the way but the group that was left really trusted Suho and he supported them heavily in return no matter what it was they were pursuing.