Go back to the. beginning with Tristan if you have that access. The starter module on moving their feet a specific way. Use those movements to get her attention whenever you lose it. No matter what else is going on, if you ask for something she must respond even if the response is wrong or you needed strong cues. You can work to get the right response from lighter cues, but no response gives you nothing to work with.
I had already found this idea before I started looking at TRT. My set of movements wasn’t exactly the same cues or moves as his (very similar), but I was using them the same way - to refocus the horse in a calm, understood fashion. The horse knows the exercises, needs to focus on my cues but is still able to keep a bit of attention on whatever is worrying. Which is okay.
Doing the known movements, with increasingly lighter cues and faster changes between moves helps the horse by giving them the opportunity to realize the worrying thing is not threatening them. Speed depends on the horse in the moment as moving too quickly will increase anxiety. The initial cues may have to be very strong to capture the horse’s attention, and then can be lighter and lighter.
Having a series of moves/exercises that is used regularly (every time in the beginning) provides the horse with a mental place that will allow them to relax and think about things instead of just reacting. We can’t tell a horse to relax, and trying to do so when they’re anxious is a losing proposition. The moves/exercises need to be something the horse can do easily, and difficult enough that they must pay attention to what they’re doing/you’re asking. Eventually the horse will associate the set of moves with “it’s fine, nothing to worry about” and will relax as they do the first moves.
I used bits of TRT and Warwick Schiller and what my very anxious QH taught me to work with my younger horse. I wish I had known this stuff when I had my QH.
I realize you’re not asking for training advice and my response strays close. The exercises you get from TRT or WS or anyone else aren’t going to provide the results you want until you figure out how to use them as tools. in various situations, and modify them to suit your horse. It took me a while to figure out how to apply WS’s rabbit theory to my horse, and longer before I saw more than small improvements, but sticking with it was worth the effort.