A country or nation state would never take responsibility. They have to cover their track so more than likely it was China, Iran, US North Korea. Russia. Only nation states / countries with enough power to take down an infrastructure like X.
So, of course, somebody’s gonna chirp up quickly to take responsibility because we would have an international incident if one of those countries was identified as the source attack.
Use logic… if you can’t figure it out yourself ask Grock