Sorry, I don't suggest following forum relayed rehab specifics.
In general, any strengthening exercises are good.
However, you need to at least go talk to a rehab specialist. (they are almost always quite willing to give free advice on area specific exercises)
It's not just a matter of which exercises to do, but which ones to avoid, and which equipment to avoid.
Rowing machines are great, hand weights with the arm going straight to the side and up are good, same with going back with the arm.
Google shoulder girdle exercises, and that may give you a lot of ideas.
Thank you so much EdwardPB. Can you recommend at home no equipment exercises to strengthen my neck and shoulders?
Yes, exercise and strengthening are the number 1 solutions, and ONLY solutions.
Even after problems are corrected by surgery, they always need exercising and muscle strengthening afterwards, to complete the healing and recovery.
All other options are managing, not solving.