From my point of view, they can't even "just turn on the Internet", even if they wanted.

We know from the Ukraine side that "keeping the internet on" requires a whole bunch of personal sacrifice, and a lot of "reasonably recent" electronic equipment and infrastructure that Iran can't simply buy or repair right now.

I'll bet you - dollars to donuts - that Iran has many countrywide IP-based networks running at this second, for things such as broadcast and telecoms.

Perhaps you are underestimating the resources available to a country of 90 million. You could play a game where you estimate the number of routers and switches outside of Tehran under a hypothetical where the the capital was leveled. I don't know how many universities Iran has, but my working assumption is that any one Computer Science department from a D-Tier university is equal to the task, if the physical carrier medium for the Internet is still present and they are bringing their ancient half-rack of equipment.