The "leaks" occurred just outside Danish (NATO) territorial waters, but within the Danish economic exclusivity zone ... a perfect spot for a false flag operation to blame NATO, or its members.
If NATO, or one of its members, was going to sabotage the pipelines, but maintain more plausible deniability, it would have been better to do it in Sweden's economic exclusivity zone.
Why is so important to believe the West, NATO, or the US is responsible? The only reason for such a belief is to justify activity against the West, NATO, or the US; or to garner sympathy for Putin's cause.
If the Russians truly believed or had proof that the West, NATO, or the US was responsible, the Russian embassador to the UN would be pounding his shoe on his podium.