Do note … I don’t have kids nor am I blessed to be a parent so take my advice with a hill of beans :)
The harder you push and discipline, the more she will rebel against you.
Give her a small allotment of money, and make her pay for her own cell phone bill and technology kit. You can use a service like Google Fi where you can pay as you go (and I believe you can even control the data to the phone). Get a prepaid visa card to setup to pay the bill and make her responsible for making sure there is money in it.
Then at home …. control the wifi. There is equipment (e.g. from Netgear) that you can setup that controls the times and speed and content). This way you can limit the exposure on two fronts.
Then … spend the time to sit down and go through everything with sex (the pitfalls) …. e.g. in the news today talk about Epstein’s female handler and how girls will sold into sexual enslavement. Show them STDs and other nasty aspects of it (it maybe squeamish but that is the point).
Then state … if you are interested in this boy …. have him come over and you two should take pictures together and oh BTW …. we are going to have dinner and there will be a discussion on sex with all of us.
Then state …. your body your rights … but we love you and know people out there want to use you and disrespect you …. always come and talk to us …
My 2 cents … if I had a daughter or son … I would probably talk and go down this path (which I know probably would fail or would be naive ….) but it is what I would think about doing …
My intent was to try to give some ideas (brainstorm) to help … not micromanage so ….. take it or leave it … and I am sorry you are dealing with this maelstrom.