I have never suffered a serious shoulder injury, but speaking from experiences with weak shoulders. I feel the best overall exercises to help with shoulder issues are the ones less widely used. I would make face pulls (rope face pull aparts) a staple in my routine if I was looking to build back my stability in my shoulders. A must in my opinion for a healthy rotator cuff, and healthy pressing. I would also advise to stick to Dumbbells to help build stability, as certain grip variations (neutral especially) can help with any residual shoulder pain you may be feeling. Landmine presses, and seated shoulder press (from the floor, in a squat rack with no back rest) are favorites of mine that I've learned from CT's articles.
You may be dropping the load, but sometimes less is more when emphasizing shoulders. Starting light gives you a chance to fix any imbalances, or weaknesses you may have had before your surgery. It gives you an opportunity to start over and rebuild. Which in the end may give you stronger shoulders than you once had. Good luck man! Hope all goes well