I became disabled due to chronic fatigue syndrome, and as I progressed until gradually unable to keep a job, I also went through what you are of being denied disability benefits, but a good doctor (specialist) helped me w/ an attorney referral, which along with letters from former coworkers. HR and family as to my condition, some careful record-keeping (hard and draining), and being able to stay with family until things stabilized more, were a big help when I went to the administrative law judge finally about it. My security is church and family, family and church (and given the government's track record, that is where it will stay--maybe states could do better, but I don't think the US fed ever could--long set of experiences there).
So I can sympathize: even though our conditions are different, I think there is some overlap. For my situation at least, graded exercise therapy or the belief it is all in one's head, are very unhelpful ideas (much could be said).
But now things have stabilized, I believe I will get better eventually, and there is hope for me, and there is hope for you. Don't ever give up.
Here is another recent article (related to overcoming depression with a multi-pronged approach, not trying to do everything at once but in thoughtful steps), which I thought was very good (has some religious aspects, which are actually relevant): https://www.churchofjesuschrist.org/study/liahona/2022/07/07...
Again, don't give up. It can really get to where things are OK.