It's still not confirmed who did that. Self sabotage by some European nation or even Russian is still up in the air.

Destroying that pipeline pushed Germany to act more against Russia (being officially unable to continue buying gas).

Historically anti russian states like Denmark, Sweden, Finland and Estonia or even NATO would have liked that.

Russia could have blown it up themselves to pin it on Ukraine to decrease support, but that doesn't seem to be the outcome.

Even germany could have blown it up to pivot their own politics.

It's a massive game of clue. It may become declassified in 20 years by whoever did it.