I detested CBT. Why would I benefit from a bunch of badly photocopied and creased worksheets with cartoons and a guided sitting still in the noisy room (with my now-ex standing outside the window) to 'help me' handle 'uncomfortable feelings' when the uncomfortable feelings were that I was being abused? And why tell somebody off for not doing their homework (called that, too) when if you'd asked it was because I'd already had the first degree about what I'd said about him in the previous session and knew if I listed each time I failed to stand up for myself on a piece of paper, it would have been found and there would have been hell to pay? Not that you were allowed to speak of specific incidents - that was banned. It was an integral assumption from the outset that any unhappiness was purely because you were inadequate and entirely at fault for any negative behaviour from others, not that you were perfectly reasonably reacting to a barrowload of shit that you didn't deserve.
I also despise the commercialised form of mindfulness. The actual practice as taught by a Buddhist who also had autoimmune arthritis was great in dealing with pain/the fact it's going to be there (although that could just be because I'd never had anybody say to me 'yes, it's shit' instead of banning any thought or mention of it and instructing me that it meant nothing, it's all in my mind and look at paralympians, they don't let their disabilities bother them, do they/it's all about your Growth Mindset/why aren't you as positive and joyful and able as the world class athlete of caring, well off parents?) - but the buzzword version is utter shite on a par with 'think pretty thoughts and pretend it isn't incredibly painful to sit absolutely still on a plastic chair for five minutes in silence with somebody looking at you'.
What you're going through is shit and you have lost so much.
Is there any way you could claw back some of it in a different way? You're not being abused by parents or (hopefully) ex anymore? If you've had horses, then practically, do you have the income to look into any form of carriage driving, having horses cared for by a stable with disabled access where you can be with them, outside? Could a robust, all terrain wheelchair be within the scope of possibilities?
Are you trapped inside? I could imagine that being unable to get out would be bringing all those feelings about being trapped with abusive parents and ex to the front of your mind. So perhaps it is finding a way of being outside that will help - access, movement (electric wheelchair?), transport? Is your home actually accessible and could you move around it and get out of it when you want?
Would houseplants be a way of gardening that's more manageable?
If your reply is 'but it's not the same', no, it isn't. But could it help you get some of the pleasant feelings?