Who the fuck cares about cargo before trying to figure out if any second stage rocket that isn't a rock can reasonably survive the extended application of high G-forces
They have some data that indicates most off the shelf electronics survive or need very minor modifications to withstand the G forces. That's better than no data at all but they do have a ways to go.
It's not just g forces. It's combination of g forces and atmosphere drag. Drag forces during launch could be bigger issue.