I have recent experience with both rotator cuff surgery and Shockstop stems.
I had rotator cuff, etc. surgery early March of 2020, just before the pandemic halted most elective procedures. I stayed off the two wheeler until given the go-ahead by the doctor, whatever benchmark he had for "fully healed / as strong as it could be", which was about 3-4 months post op (I had the sling on for 6 weeks, then another couple of months healing and PT. I just followed whatever the surgeon said, but really can't remember too clearly the exact timeline, sometime in the middle of the summer.
Anyway, before the snow melted and while I still had the splint, I walked many, many very hilly miles (150 miles in April alone). When the snow melted, I bought a recumbent "tadpole" type trike. I bought a Performer brand which is a decent quality "real" recumbents (as opposed to the $200 ones with grocery baskets on them). It had free shipping cost and came unassembled, so that gave me a fun project. It was fun riding the trike and giving it a try. I did hit 40mph downhill on a curvy smooth paved road! Uphill it was a real PITA.
Anyway, I rode the trike for a couple of months after I got the sling off, and then got on the bike and sold the recumbent for just a few hundred $ less than it cost. Worth it for a couple months use and to try that sort of ride. If it hadn't been snowy and icy in March and most of April, I might have ridden the trike with the sling on, but as it worked out, researching, purchasing, receiving, assembling and waiting for the ice to melt got me past the sling phase before I got on the trike.
Once I got on the bike, frankly, I didn't feel nor haven't felt any discomfort or stress on the shoulder. Before the surgery, I couldn't raise the arm to signal a turn, but it didn't really cause any discomfort other than that. Afterwards I can ride and signal turns without appreciable pain or limitation. The risk was falling and damaging the shoulder repair before it reached the benchmark where the doctor felt the repair fully healed and strong which is why I was conservative. Not that it couldn't be hurt, but no more "fragile" than a healthy shoulder.
I do use a Redshift shock stop stem on my gravel bike and am thinking of getting a couple more for my road bikes. Not for the shoulder - I really don't think they contribute meaningfully to shoulder comfort. But I have arthritic elbows due to old injuries which actually can get painful sometimes when I'm riding, and the Shockstop does help with that, especially on chip seal and gravel.