>> it generally makes absolutely no sense for Russia to be behind this
Of course it does - Poland is entirely relying on the Norway to Poland gas pipeline, if that goes then a country of 50 million people has no gas this winter. Blowing up the Nordstream was(to me) a clear signal that EU needs to be careful or the Norwegian pipelines are going up next.
Do you really feel like "send a clear signal that EU needs to be careful or the Norwegian pipelines are going to be next" is a more plausible motivation above "permanently end European reliance on Russian energy"?
OK, let's assume that is the case. Now the EU is very careful about the Norwegian pipeline, and surveillance of this pipeline dramatically increases to defend it from potential Russian sabotage.
You can't effectively defend hundreds of kilometers of an underwater pipeline, you can only increase monitoring but that doesn't stop the pipe from being blown up. In fact the charges could have already been placed, before any extra monitoring was deployed, and are just waiting for a signal.
The point being - Russia has sent a very clear message that if we don't stop pushing back on Ukraine, that pipeline is next to blow up. There is almost nothing we can do to prevent it if they want to make it happen.
I mean, that's not how Russia operates. They poison government critics abroad using a compound only they could possibly have, and then say "it wasn't us". They want everyone to know it was them, without saying it was them explicitly - that's just not what they do. Even if a Russian submarine blows up the Norwegian pipeline tomorrow, with recorded footage of it happening, Russia will still say it wasn't them.
What has Russia gained from any of their actions thus far in the war in Ukraine? I wouldn’t discount something solely because it appears to be a short sighted action that backfires in their face.
Nord Stream is 51% Russian (Gazprom). Not sure if it is NATO territory or international waters. It still becomes a little bit more "muddy" on who could have made it and who benefits from it.
Attacking Norway-Poland line at this point would be a very obvious and very direct attack on NATO.
This is all motivated thinking with "It's Russia!" as the end goal.
Some of the NS attacks were on NATO territory. Denmark could invoke Article 5 were it found to be Russia. If "NATO" were in the equation, the saboteurs would have stayed in Swedish and Finnish waters, and even then it's iffy.
Of course it does - Poland is entirely relying on the Norway to Poland gas pipeline, if that goes then a country of 50 million people has no gas this winter. Blowing up the Nordstream was(to me) a clear signal that EU needs to be careful or the Norwegian pipelines are going up next.