Tbh unless low orbit debris density is truly ridiculous, a rocket launching directly to earth escape probably could make it out. You have, on fermi estimation, ~1e8 m3 of volume swept out at LEO altitudes, so you'd need on order 10 large enough pieces of debris per km3 to make launching stuff out impossible
Plus a supervolcano wouldn't be able to launch debris into orbital trajectories, tbh not sure if it can even get debris up to orbital altitudes to start a collision cascade