Sometimes we can have more than 1 thing wrong with us and it sounds to me like the surgeon knows the RC area is sound now. Give your body a good 1.5-3 years for healing. I believe that some surgeons assume the healing process to be faster than it actually is, and this leads the patient to depression when things don't get better as quickly as they want.

Therabands... if these new, easier exercises are still making you worse, stop and tell your PT people. Ask about Feldenkreis PT (do a search on it in this forum to learn more) as an alternative to strengthening exercises. It will keep scar tissue from adheering to things and give you the range of motion that you need.

TOS is a 'syndrome' and possibly this RC surgery made nearby muscles and nerves angry, which now are causing the classic TOS symptoms.

Which fingers are numb? Was/is your pain properly addressed? Are you sleeping ok?

Anne