I dislocated my left shoulder and split the bone in my arm at the same time.
NHS missed the bone damage at X ray time so when they identified this, the bone and thus tendon has re-set in the wrong place.
I was back on a bike within 6 weeks (against all medical advice), but rode very gentle stuff for a long time as any rock descents, jumps or anything with big impact or effort was difficult. Lots of little rides with a very gradual ramping up of severity of terrain got the strength back into my arm.
It’s taken a lot of very intense physiotherapy which hurt lots to get the tendons sorted out into the right place. It was three years before I could get full range of motion back into my shoulder. Pretty much did for my cricket career.
Long and short of it: Shoulders are difficult injuries to diagnose, treat and recover from.