Deliberate bad behavior

I am at a complete loss. 11yo girl just absolutely will not act right. Sometimes it’s little things that just compound until you’ve lost it other times it’s big things at you have been thru with her over and over again that she just will not comply with. Short backstory my niece lived with a foster mom longer than she had been with her own mom or grandma. At the time she entered foster care we did not have the means to take her and provide the care and raising she needed. 4/5 years later we were approached again that she was needing a place or there was a threat of her being placed into the adoption side of foster care. We had been able to settle a lot during that time so we made the commitment to bring her into our home. (There had been time earlier we could have done this but didn’t simply because we had been led to believe she was doing so well in that home and didn’t want to cause her any harm by uprooting her again) We quickly found out she had not been doing well and her foster mom had just finally reached her wits end with her and her destructive behaviors and put her foot down with DHS. None of this back information was available to us before taking responsibility for her. So we immediately had her in with counselors, therapists medical professionals to try to sort things out. After nearly a year, most of them came to us with, we do not know what to do with her honestly. She shows all signs of being fully aware that she just deliberately chooses not to go with the flow, to purposefully cause trouble on any level, and sometimes just seeing what she thinks she can get away with. She seems to get a rush over feeling like she got always with any kind of misbehavior. The few times I’ve been able to have an open conversation with her about her choices it boils down to she just wants to be free to do what she wants 😳 like sorry but that’s not reality, and she has a long life ahead that that kind of thinking just won’t get anything but chaos and trouble. I honestly do not know how her foster mom dealt with her for so long. We are close to 2 years in and have gotten nowhere and it makes me crazy. Sadly professionals just scratch their head with her so how am I supposed to deal with it if with all of their education don’t even know where to begin, and pretty much get to a place they won’t even try anymore themselves 😭

Just keep reaching out for more help I guess 🤷🏻‍♀️ until she pushes it too far with the wrong people or wrong place and end up in major trouble like she’s been told will eventually happen.