You’ve gotten a lot of good advice already. But something I would just add is the importance of prioritizing routine and habit. It’s easy to get caught up on the moment-to-moment progress you are (or aren’t) making with different training approaches. And when you’re so invested in the moment, you may want to try throwing every possible thing at the wall to see what sticks, and to continuously go back to the drawing board and try new things. But I just want to stress how counterproductive that can be. Even if you are doing something the “wrong” way, as long as you are consistently wrong, your horse actually has a chance to learn what you want. There are a lot of roads that lead to Rome! But if you second guess yourself and repeatedly double back, you’ll never get there. BTW, this isn’t related to anything you’ve said in your posts, it’s just advice that I know I would have wanted to hear when in your position.
But there is one thing I’ll say that is related to things you may have insinuated in your posts. Don’t drop your standards for this horse. Horses have an uncanny way of living up to—or down to—your expectations. Of course it’s important to investigate any sources of pain that you can fix. But try to be careful you don’t cling to a narrative that gives you permission to overlook problems you should absolutely be able to work through. FWIW, in my personal experience, I think I misinterpreted a piece of horsemanship wisdom “reward the slightest try,” by taking it to mean, “reward generously even the most half-assed efforts.” Compromising and accommodating quirky or anxious behavior does not end up helping the problem at all. Part of being clear and consistent is not compromising, and that clarity and consistency is really important to establishing the habits that are prerequisites to making a calm, confident horse!