I would guess you'd do something like try and cast any electrical components in something like a resin so it's just a solid brick that can handle the stresses. But 10k G is a lot.
This technology seems to be suited for launching moderate numbers of small satellites. It's not a huge win on launch cost over filling up a Falcon 9 with racks of small satellites.
This competes with the Pegasus air-launch system, where a rocket is carried to high altitude by an aircraft. That works fine, and launches have been going on since the 1990s. But it's not a huge financial win.
It's good to have a few competing technologies. Keeps the price down.
Most satellites are unique, so the same can't be done. Besides being weight critical, every failed satellite becomes space junk.
With regard to weight, they say this system works best with very dense payloads. But that's only for the spin/toss stage; it doesn't account for the rocket booster needed to actually bring the satellites into orbit.
As for testing, engineers don't need as much empirical testing anymore, since we have very good computer simulations now. Most of the satellites launched with this would probably be variations on a handful of designs. But I don't understand where the demand for such a launch system comes from anyway. There is only so much demand for school project cube sats; communication satellites launched this way seem dubious (not least because you can launch dozens/hundreds of them at once with a rocket like Falcon 9 or Starship)
Pressure and ballast balls.
They conclude by placing a digital camera in their lab mockup and taking it to 10,000g.
This probably would not have worked for a phone, but they seem quite confident.