That article is a pay/subscription site so I can't read it, if someone wants to post then we can look in more detail. However, your statement about this as evidence and no Russian involvement seems is based on this statement: "New intelligence reviewed by U.S. officials suggests that a pro-Ukrainian group carried out the attack on the Nord Stream pipelines last year, a step toward determining responsibility for an act of sabotage that has confounded investigators on both sides of the Atlantic for months. "
So "new intelligence reviewed by U.S. officials"....Let's say that Russia sent false "intelligence" or reporting and do you know what we do with that. We review it. All sources and their individual reports are given levels of confidence. But all are reported and all are read and true or not they provide insight. Need to read the article but does it say U.S. intelligence agencies (named agencies) state that they believe Pro-Ukrainian elements are to blame? My guess is it doesn't.
So what we likely have here is Russia or pro-Russian sources sending information to various intel agencies, then leaking or having someone leak that this intelligence exists to a press member who is happy to get a headline story with no work/validation required. Is it real, fact based....well, based on Russia I would say no. But definitely not definitive if it is just "reviewed intel".
But again, the article is behind a paywall/subscription wall. But I did work for awhile in the Intel community.