All Starship test launches are suborbital so if anything goes wrong, the ship and debris fall back to Earth.

Even if it was put in orbit, debris are not an issue because orbital decay at Low Earth Orbit (LEO) is significant. A satellite orbiting below 250km will fall back to earth within a few hours, and at 400km within a year. LEO below 500-600km has enough atmospheric drag to be self-cleaning.

Debris issues are more significant at higher orbits 800km and above.