This wasn't done to coerce European countries. This was done to stir chaos and make it look like someone other than Russia committed sabotage.
Then again, Russia might not have the monopoly on stupidity.
Why would Russia invade and annex Ukraine? The answer can be stupid people making stupid decisions, don't assume everything done by a nation-state is logical.
They had good reasons to maybe want to dominate their neighbor. What good reasons were there to risk everything over an all out land war, and what reasons remain for continuing a fight they are losing ?
This is predicated on the assumption that the US intelligence community would leak it anytime soon (within the current presidency). That seems like a very poor assumption. If it's never proven they did it, there's no real risk because people who don't want to believe will invent other explanations. You see it happening in this thread already - it's not the country that literally said they had ways to ensure NS2 would never activate, no, it must be the country that built it. 4D chess!
"These pipelines weren't deliving gas anyway"
No, but that could have been changed very quickly if wanted. All three pipelines were pressurized. NS2 was all new equipment, ready and waiting to go.
"The US would prefer energy markets to be stable and not have sky-high prices"
The US has consistently and strongly opposed European dependence on Russian natgas under (at least) two different presidents. Neither of them seemed to care much about the question of what to replace it with. At any rate such an operation would be signed off by Biden and highly classified, so it's not like "the US" would have an opinion on what matters more anyway, just a senile old man.
Some people think the 'official story' isn't right. Like it's often the case, and sometimes for good reasons.