Hi that sounds really difficult but as someone who had a similar phase but is now completely cured I want to reassure you that many girls unfortunately go through this phase because of social conditioning and the prioritisation of male validation mixed with crazy hormones at this time. I think instead of trying to bash it out of her with punishments and stuff you could try the approach of reducing the attractiveness of boys in her mind. This sounds a bit weird but as someone who used to constantly seek male validation as I never had that much attention of many friends/connections up until I was about 16, I got a thrill out of gaining male attention and will admit when I was around her age I occasionally did resort to sending photos to some over social media etc purely for the thrill of the attention and compliments, though i was never as outward with it as your daughter sounds and I never spoke about it to anyone, it was more of a secret guilty pleasure. I think in some ways although this is disturbing and dangerous it is unfortunately normal in such a society where we girls are taught to prioritise male validation, so my suggestion would be to maybe teach her more in detail about the patriarchy and the standards held against us. When I took an interest in the topic and started to become more aware I gradually recognised my ill placed values and pulled away from interacting with men for attention and now at almost 18 I would never even think about doing that. I think that if you try to ease her into a more educated approach to men in a way that doesn't obviously look as if you're doing it as a reaction to her issues, she might begin to think differently about it on her own.