So the main anxiety comes from being alone? Cause Buffy was a hot mess when I got her but that was mainly outside. 🙂
Have you tried a Thundershirt? I found it helpful when I trained Buffy to ride the bus. Or maybe get a neighbor to watch her when you're out? (I know some people who don't mind the dog not being able to be alone and just arrange for it to be watched)
If I were you I would take it very step by step. I.e. leaving him for five minutes, training this whenever you can, increasing the time and then working your way from there. That is obviously time consuming but might be worth it.
Also, my biggest tip here, is when you come back from wherever you've been - utterly ignore the dog. Don't make coming home a big deal. Just come in, do your thing, and maybe after five-ten minutes (when the dog is calm or wait for however long it takes for him to get calm) then you greet them. If you coming back isn't a big deal then you leaving doesn't need to be one either 🙂
As for the pulling, oh man, been there! Tried harnesses and candy and bugger all! What worked best for me was another time consuming methodical process. I would set a goal - like between two lamp posts - and for that short duration I would block my dog with my legs, i.e. stepping out in front of her, and ignoring her attempts to get past me, and walk with her in a short leash by my side. This is frustrating(!), and you look silly, but in small installments it is possible. And it's the same here. You try to increase the distances with time, as the dog starts to understand what's expected of them.
Also teaching them 'stop' helps. I often walk Buffy on a 65foot line (so she can't take off hunting) and the cue 'stop' is imperative if she starts running, if she sees something interesting, etc. It's made her used to hearing 'stop' (sometimes substituted with various 'slow your roll missy' noises. Such as 'hupp!') when she's on the regular leash as well and will make her halt her strides if she's started pulling.
Hope any of this helps 🙂