The immediate ramifications of shutting off Russian gas would be akin to 1920’s depression. And German economy going to shit means the rest of Europe and Euro itself tanking.
If they declare force majure and seized a boat to ship now, there would be hell to pay for some other consumer.
So they can make big inroads into their static gas consumption by rolling with that and shutting down some or all of their gas power stations instead... it seems they have options to trim their usage to the point they can prepare for winter without funding their own security threat.