You misunderstand Kessler syndrome. It doesn't "trap us on this planet", all it does is make certain orbital regions no longer hospitable to satellites orbiting within those regions. Launching through those orbits would be fine, the payload passing through them wouldn't spend long enough in there to be at significant risk of impact. You only get an unacceptable risk of impact if you remain there for years.
Also, Starlink satellites are at a low enough altitude that if they were to be disrupted the bits would fall out of orbit in a matter of months. That region is basically Kessler-proof.