It's different for everyone. See three different ortho docs, you'll get three somewhat but not radically different opinions.
Surgery wasn't an option after my shoulder break and Grade 4 dislocation last year (I couldn't be intubated for anesthesia). By the time the trachea problem was corrected the shoulder had pretty much healed.
I spent most of last summer on the indoor trainer and finally got back on the bike after about three months, at first on an upright hybrid, then gradually more rides on the road bike.
At age 61, mine took much longer than I'd expected to not only heal but to stop hurting so much. It was darned near impossible to sleep or do anything for months. But I've been in physical therapy for six weeks and it's gotten significantly better. Less chronic pain, better strength and mobility.
There's still that distinctive ACV joint knot that almost everyone gets with shoulder injuries. That's permanent. But if I can avoid surgery or joint replacement I'll be satisfied.
In contrast a friend who's in her early 40s has had two serious shoulder injuries in the past two or three years and was back on her bike and riding faster than I can go in only a couple of weeks.