I've found that puppies don't tend to stress growth plates just from being puppies. The big things that risk stressing growth plates are intensive, repetitive, or high impact exercises like jumps and weaves in agility or running on a leash nonstop for miles. I've raised several Rotts and GSD's at this point and all of my puppies have been given plenty of exercise outside. The big thing is that they are allowed to rest as needed and they aren't made to do anything high impact or intensive. My past ranch Rottweiler puppies followed us around all day long, running through the fields, jumping over logs, chasing the calves and lambs, but they rested as needed.
I think the biggest change I've made since moving to the city is going out of my way to avoid walking too much on concrete. This is the first puppy I've raised in the city and while I don't personally have experience raising puppies around this much concrete, I've been told intensive running or super long walks on concrete or asphalt surfaces could be too stressful for growth plates. So I just find hiking trails, parks, nature preserves, anything that has good old dirt to run around on.