How can I deal with my sister’s behavior and why is she like this?

Assalamu alaykum, This is anonymous so I’ll share honestly. My sister might as well be fictional sometimes😭😭. I won’t say her exact age but she’s in high school. She doesn’t wear hijab and doesn’t want to. She says “yeah i do,” but it’s just talk. She wants to go out in revealing clothes - tight dresses, crop tops, tank tops. Today she wanted to wear one of those baby tops or whatever they’re called. My mom and I keep telling her it’s haram and immodest, but she doesn’t care. She always complains about Islam being unfair to women, like why can’t we wear perfume or jewellery, and so on. استغفر الله Could she be like this because dad wasn’t around and mom let her do whatever? Some backstory: - I went to an Islamic school from pre-k to 11th; she only went to 8th. I grew up loving Islam and begged my parents to let me wear hijab at 11. They said I was too young but I wore it a month after my 12th birthday and have kept it up الحمد لله. - My sister never wanted to cover. She says she’ll wear it after marriage, which I doubt. She didn’t like Islamic school much. When younger she loved learning about deen but that faded. She wants to do haram things like go to concerts and celebrate Halloween. - Dad was strict with me and told me not to wear makeup or short clothes, didn’t let me go out without a parent, didn’t allow social media or a phone. He was barely around after I was 8 though. He never lived with my sister; he went to prison when she was about 6. - My sister always had an iPad, social media and a phone by around 8–10, so she was more exposed to outside influences. - Mom rarely disciplined her. Maybe she felt guilty about how she treated me. She hit her very rarely and mostly avoids confrontation because my sister throws tantrums. I tell mom she’s enabling her, but mom thinks she’s doing the right thing. Example: we once caught her doing really bad stuff on her phone. I took the phone away and she flipped out for days. After two days mom told me to give the phone back. I’m the eldest daughter and basically run the household - I pay bills, pay for her schooling, manage the house. When I try to discipline her she says I’m “just her sister” and I can’t tell her what to do. Even though I do everything, she refuses to respect me. Once a potential match’s family checked my sister’s social media and decided I wasn’t suitable because of it. That was heartbreaking. I’ve tried advising her but nothing works. She doesn’t care about modesty, authority, or much else except doing what she wants. My questions: - Is she like this from a lack of male authority? - Are girls of her generation mostly like this? - What can actually be done? How can we fix it? - Is it my mom’s fault? - Why is she like this when I wasn’t? We’ve thought about sending her to an uncle’s for discipline, but that’s unrealistic - uncles don’t know the full story and already dislike us a lot. What can I do? Edit: I want to clarify she isn’t completely lost - she still has iman and follows the deen and doesn’t commit major sins, الحمد لله. We all struggle. I just want advice on helping her and correcting behavior, not harsh comments. This is one side of the story and I’m asking for constructive help.