So sorry you are having trouble getting a handle on her anxiety.
I don’t have a lot of experience with this, but will share that about 3 years ago Cali was attack by a hawk and she fought for her life and won, but we went through about a year and a half of significant anxiety issues. Today she is totally anxiety free - well, except for those pesky fire works
We used the liquid Xanax, titrating the dose down over the year and a half. Was not cheap, but was very successful. We could only get the liquid at one pharmacy and they had to order it for us. It kicked in quickly and being liquid we had great control over the dosing.
Have read that others have not had the success with the Xanax but it was perfect for us and really worked.
Hoping things get better for your little girl!