The internet does not go from A -> B it is a web. You can (and some countries do) cut yourself out of it. But you cannot cut others out of it.

Solar generation of power across countries will pretty much go one way. The most obvious and likely one is from North Africa to Europe. If the North African states decide to turn off the power to Europe they can. This is why geo-politically you cannot rely on this as a 100% solution. It can add to a solution, but it is not a good idea to let another country hang a sword over your head like that. (Or more precisely to hang the sword there yourself)

The infrastructure scale is not even in the same ballpark, or even neighbourhood.

Besides the fact that you can't just "make" internet from a coal/petrol/etc generator somewhere nearby.

Imagine a ship's anchor damaging a cable carrying a couple megawatts of power (this happens frequently to the undersea fibre optic cables, and even those are a nightmare to repair).

Internet connection doesn't suffer as much power loss over larger distances