For rotator cuff disease, subacromial steroid injection was demonstrated to have a small benefit over placebo in some trials however no benefit of subacromial steroid injection over NSAID was demonstrated based upon the pooled results of three trials.
For adhesive capsulitis, two trials suggested a possible early benefit of intra-articular steroid injection over placebo but there was insufficient data for pooling of any of the trials. One trial suggested short-term benefit of intra-articular corticosteroid injection over physiotherapy in the short-term (success at seven weeks RR = (, ).
I don’t believe that the body can grow strong due to tendon/CNS adaptations as you keep asserting. That may work for a few weeks when you begin a new exercise & improve motor skills and structurally adapt, but it will not last long. You will never get strong in the long run if your muscles are not also growing. But I think many people have vastly overestimated the impact on your appearance that gaining muscle actually has. Gaining 5 lbs of fat will make you appear much sloppier, but gaining 5 lbs of lean muscle will not make that much visual difference while wearing clothes