Blow up all gas pipelines from Russia. Cut them off.
Umm wtf now you want to cut Europe from gas

Dont think taking Europe hostage is a good idea
You have to pressure the oligarchs to stop Putin's adventures.
I suspect he will drop a nuclear weapon very soon. The only question is where. Probably somewhere away from the future Russian Empire territory. Maybe some military base on some island away from everything.
You appear to be very emotionally involved in this conflict, which is understandable, but it looks to be clouding your judgement. EU and US indicated that they do not want to make this regional conflict into a global one. There are always two willing parties to every transaction. EU continues to purchase gas from Russia, and over Nordstream 1. Ukraine trying to terrorize people into direct conflict by blowing up pipelines going to EU, will surely be counterproductive to Ukrainian cause. If anything to make up for lost capacity they'll be forced to turn on Nordstream 2
Germany is already looking at alternatives. Both pipelines will be closed. The issue is the timing.