Please tell me there’s hope for reactive rescue

We got a 3-year old shelter dog a couple of months ago and have been working with a trainer diligently. We’re following protocol and staying committed, but walking the dog is still easily the worst part of my day. She’s knocked my wife down a few times, landed me on my ass, and generally goes into full-on meltdown at basically any stimulus. We can’t take her to the vet, groomer, or pet sitter because everyone is terrified of her. We can’t have people over to the house. It just generally feels like our life has come to a screeching halt and I’m starting to lose it. I’m sore after walks, and my hands feel like I’ve got arthritis. I also live in fear of her getting away from me, knocking over a child, and getting me sued.

She is a 65lb Boxer mix. We’re using a martingale collar and keep her leashed in the home. We’ve worked hard on keeping our own stress reactions in check, have eliminated most voice commands in favor of leash only, and have stayed on a very regular, predictable schedule with her. Our trainer has prescribed times for us to walk her, we have set routes, and do a fair amount of predictive stimulus avoidance. We make a lot of u-turns. We also have been working on watching her instead of the environment to anticipate her stress level and reactions. We feel like we’re seeing zero progress, and our trainer is feeling the same. We’re also working in the home on building trust with hand feeding, basic command training, high value treats, and plenty of play.

The positives are that she’s housebroken, is good in the crate (except right when we leave), is good with just chilling at home, and is not destructive.

Is this just my life now, though? We’ve got probably another ten years with this dog. Is there hope? For those of you who adopted reactive adult dogs, were there key turning points for you/essential changes you made in your approach? Are we looking at years of work? Is there at point at which training just isn’t possible? I’ve been reading a fair number of reactivity posts on here, and it seems like many of the steps people are taking were either doing or have tried. Any suggestions would be welcome.