He did it didn't affect Europe supporting the Ukrainians. Blowing it up serves 2 separate purposes.Why would Putin blow up a pipeline Russia built, that he supplies gas to the EU with for big money, when Nord 1 was shut off a month ago, Nord 2 wasn't fully operational yet and he could have more easily just shut the valve?
First it makes the status quo as it was permant in the medium long term. Ensuring maximum disruption of European gas prices for winter.
Second it also shows that he is serious about risking war with Europe by attacking European interest outside Ukraine military without taking it as far (yet) as attacking the block directly by for instance blowing up gaslines that are exploited by European countries. This makes his nuclear threat more believable.
It's like a mobster throwing a brick through the store window of someone he's trying to shakedown. The store owner gets the message but the crime is almost impossible to prove.