Assalamu alaikum - My Sister Removed Her Hijab After Years of Practicing Islam

Assalamu 3aleykum wa ra7matuLlahi wa barakaatuh, TL;DR: A few years ago my younger sister and I accepted Islam and grew close to the deen, but recently she’s drifted away - stopped praying, listening to music, removed her hijab, and seems to be embracing a more worldly lifestyle. I’m heartbroken and not sure how to reach her without making things worse. I came back to Islam about 4 years ago and my little sister accepted about a year after me. Soon after we both started wearing the hijab and abaya. We learned Arabic basics together and were excited to seek 3ilm. She took online a7adith classes, went to halaqaat, and would recite Quran out loud while doing chores trying to memorise. I used to thank Allah for guiding her; it felt like a blessing. She was always a bit more relaxed than me though - watching TV and using social media more than I was comfortable with. I would gently remind her, but she never really stopped those habits. A few months ago I noticed her change: I stopped hearing her recite Quran, she wasn’t attending halaqaat or trying to learn about the deen, and I rarely saw her pray. I kept hoping she was temporarily distracted, but then I overheard my mum talking about a piano possibly being bought for her. I was shocked - knowing music is something many of us avoid, it hurt to imagine her wanting to play. Not long after that I woke up to a message from her saying she had taken off her hijab. My heart broke. SubhanAllah. She said she had no excuses and wasn’t trying to justify it. I replied with a message full of love and honest reminders (I’ll summarise): I reminded her to keep praying on time, to read some Quran daily even if a few verses, to keep morning and evening adhkar, and above all to fear Allah and turn back to Him. I reminded her of Allah’s mercy and that we return to Him. She took my message well and told my mum she appreciated my reaction. I know she expected me to be honest - I won’t pretend it’s fine when I’m worried for her. But since then she changed her haircut, bought new clothes to go out, and seems happy and more confident. I’m even more worried. Today I saw her music playlists and it was full of songs; one playlist title even said “The only heaven you’ll know.” My chest felt heavy. When we reverted we both avoided music, so seeing this was painful. A3udhuBillah. I’m genuinely scared for her and at a loss about how to help. I want to advise without pushing her away, to support without judging, to be a means of guidance rather than a cause of distance. If anyone has calm, compassionate advice on approaching her, what to say, or ways to gently encourage her back to Allah, I would greatly appreciate it. If you think I’m overreacting, please don’t comment - I’m asking for sincere guidance only. JazaakumuLlahu khairan.