Muscle Atrophy? Possibly irreversible?

Some surgical procedures can be worse than others for muscle atrophy. For example calves can seemingly be impossible to build back after Achilles surgery. Others like knee surgery can result in mysterious inability to fully reawaken muscle like good knee.

How bad is it with rotator cuff repair? In this case partial, but fill thickness supraspinatus tear. Anyone know what it might be like for middle aged/older who workout 🏋️ for years before?

If muscle does not recover to baseline soon enough after a surgery, a degree of atrophy can be permanent. Assuming atrophy of chest, back, shoulder traps, tricep, bicep 😢. What are safe yet best muscle exercises before surgery to build?

Anyone know if docs suggest medically guided legal steroid stint to get back to baseline after, or even before as preemptive rehab? Or is that just crazy?