Earlier quoted context omitted.
Your theory just doesn't check out. With the pipelines destroyed, Russia can't blackmail the EU with energy as easily as they could before. And why would they destroy infrastructure that they poured billions into when they could have just turned off the taps any time they pleased? The pipelines now being destroyed is a really bad thing for Russia, a worse thing for the EU and a great situation for the USA (and Poland…
It's called burning bridges. Both domestically and internationally. It signals that Russia is committed to seeing the war through regardless of what the West does and it consolidates power domestically by discouraging any potential conspirators from acting against Putin since destroying the pipelines makes it virtually impossible for any replacement to resume delivery of gas to Europe
Putin wants Europe to cave this winter and use the leverage of turning these pipelines back on to get them to stop suppporting Ukraine.