What does a doomsday level cyber attack look like?

The concept of cyber warfare is not new, but under the cover of the war in Ukraine attacks are increasing and the stakes are getting higher for both telecoms and the wider world, argued Eric Hart, Manager of Subscription Services at LogRhythm in an interview with Telecoms.com.
Has there been a rise in the amount of cyber warfare activity since the invasion of Ukraine?
Cyber war activity increased even a little bit before the actual invasion took place. We’ve been seeing elevations overall,