We have to make a distinction between social media and passive entertainment done via screens. While both have a negative impact, social media is way more dangerous. Due to aspects you already know- online bullying etc. but also because of the addiction factor is 10 times. Dopamine gets triggered when our posts get likes and comments on social media. This dopamine is the reward pathway of the brain. when triggered, it is like a drug. We crave more of it. Since events in real life do not trigger dopamine to such levels as social media likes, the child is unable to leave it. To break this, we must give the child social interactions. These give dopamine kicks to the child too. Laughing with people around us, talking, gossiping. All this helps break social media addiction. Plus, time in nature sounds like a desire to fit in. Please work on her self esteem. You will have to inoculate her against peer pressure now, else a lot worse habits will be picked up. If you think you can’t “make her understand” perhaps you should try to understand her. Listen a lot. Be patient.
Hear about all her friends (even if it is super boring). know the kind of atmosphere outside her, as well inside her head. Bridge the gap between you two. when you understand her better, things will improve. Bullies cannot be pleased.
Please let her know. Bullies will keep shifting the bar and frustrating you. You cannot be in good books of bullies. Plus you don’t want to be in their good books. they have to be dealt with more directly, assertively. Can involve school counselor.