Really playing to your username, eh. I am familiar with Kessler Syndrome. You'll note that the most important aspect of said event, is the height, at which objects orbit, as that determines how long it takes for it to deorbit. The level of risk declines precipitously the closer to the earth the orbit is, and even if there was a catastrophic cascade at the height Starlink orbits, it would clear after a few years at most.
Impact ejection can cause eccentric orbits, but at that height, those deorbit even faster.
Fortunately, the very clever scientists at NASA have long since determined that there is essentially no risk from Starlink and similar satellite constellations, because they've been paying attention to this since before I was born.