It depends on what you mean by shutting down the whole internet. There are several main back bones that if destroyed, would severely cripple the internet to the point it wouldn't be usable anymore, yet parts of it would still work.

You could poison DNS and make name lookups no longer work. That wouldn't prevent connections, but would essentially take most people offline.

always good to have a local copy of this shit

The right content would drop it like an extension cord being unplugged. Either way Starlink is now firmly established so its not the hardware, its the software that would do it. Never happen though, to much ongoing brainwashing on devices to do so. Every second young kids brains are getting FRIED. The future is looking very grim. ELE baby.