It appears that you need to work with her in a few different areas, SA, resource guarding and trading up, plus I suspect that if you exhibit some fear around her, she may sense it and this may also exacerbate the aggression.
Hopefully, the behaviourist will help, but honestly, I would have worked with a good one rather than obedience training giving the challenges you have. It's unlikely that tripping over her caused the aggression later, but hopefully, you can get this worked out soon.
Did you contact the group or anyone else who has offered assistance? They may have some suggestions too. Good Luck!