I could have writen pretty much the same post 7 months ago about my dog.
She had eaten two sofas, dispeared every chance she had, stressed me out on every walk, the wife would not walk her anymore, they gave up on us at training classes and she was so close to going. I re-read all the books I could on dog training and gave it one more go.
To tackle the walk and recall behaviour was very much as you have done go back to basics which was hard a she would refuse most treats and toys. I ended up making liver cake, hot dog cake, black pudding that sort of thing kept changing them to keep h