Yes, the warning signs were there, but the EU was merrily speeding past them, finding reasons to argue against all of the warning signs. NS2 is one of the most emblematic signs of this: it was clearly going to tie Germany's energy needs closer to an already-proven-unreliable partner (Russia), increase the ability of Russia to use gas transit as politics, countries like Poland and the US were screaming at the top of their lungs "THIS IS A BAD IDEA" and until February 2022, Germany was responding "it'll be fine, nothing bad will come of this."

So I think it's fair to say that the EU was caught off guard by Russia, even if because of the EU's willful ignorance of affairs rather than Russian duplicity.