This is possible:
The CIA warned Germany about sabotaging the gas lines. Is it “still” reasonable to assume that the USA warns in advance about something it’ll do “secretly”?
With plausible deniability, Russia might have conducted the gas lines’ sabotage. They certainly have the capability and here are the motives:
1- to avoid winter World Court lawsuits stemming from European loss of life
2- to punish and destroy NATO and the European Union/Coalition
3- to tell its objecting ally, China, we didn’t destroy one of your biggest markets, Europe!
4- to play victim and bludgeon the USA with a false flag operation
Pretty good motives, wouldn’t you say?