I think the chances of a new dark age are locally still non zero but globally very close to zero. The modern age, for lack of a better term, is cross cultural and includes science, engineering, cultural expression, and of course the internet in it's many forms and shapes. So, there are billions of people that are part of it and are sharing knowledge and teaching their offspring to be part of it. That's not going to stop happening even if some people and countries are desperately trying to do stop that from happening.

Of course those people might be locally very successful in keeping their people illiterate, poor, miserable, and suppressed for some time. You can find examples of that on most continents. But mostly, that tends to be a highly unstable situation because people don't tolerate being miserable and poor very long and inevitably come into contact with people that can teach them how to fix that. The more miserable they are, the bigger the incentive. That's how revolutions start.

That's how the dark ages ended in Europe. There were still people that knew how to read and write. The Roman empire fizzled out and moved east but it continued to exist. Constantinople was a cultured place for many centuries before it became Istanbul. And that eventually spread west again. What is now Austria and Germany actually used to be called the holy roman empire. Which was a thing that emerged out of the ruins of former actual roman empire after a few centuries of various tribes of Europe rebelling, converting to Christianity, and regaining literacy.

And that's just Europe. The Chinese, Indians, Persians, Arabs, etc. might have a few things to say about their long and interesting history. Europe was a bit of a back water for most of that.