2 year old won’t sleep

My daughter is nearly 2.5 and for the last week she’s been awful sleeping. She is being put down around 7:30 and waking up though the night and will play and sing (loudly) and slam her legs against the back of her crib. Last night was put down at 7:30, didn’t go down till around 8. she woke up at 4:16 am and was up making noise and playing despite us going in and settling/scolding her till 7:10.

By that point she’s woken her brother up 3 times and he wouldn’t go back to sleep so I got them both up. Tried putting her down for a nap at 10 and she wouldn’t sleep. It’s now 12:30 and I put her in there again a half hour ago and she’s still not trying to sleep.

I thought we already went through the 2 year sleep regression around the time she turned two and she seemed to have gotten over it. Now this. She also has all her teeth so not teething.

I wouldn’t be as bothered if she wasn’t waking her 9 month old brother up constantly with how loud she is. We don’t spank, but I don’t know how to try to discipline her with this because usually we’d do time out, but the point is to get her to be quiet and go back to sleep! We’ve tried letting her sleep with a stuffed animal, taking everything out of her crib, ignoring her to see if she will quit, going in to reassure her and soothe her...she’s scared of big girl beds (thinks she will fall out, even with the railing) so that won’t help.

We have sound machines in both rooms but she’s THAT loud that she woke my husband up (who sleeps with ear plugs) in our room down the hall. Will scream sing twinkle twinkle little star and such.

Poor baby brother is teething and already upset and she’s now disturbing his sleep even more and messing with his schedule.

Anyone go through this, or have any ideas for me to try?