Ah, nice illustraiton by Die welt: a Russian threat. "Look what happened to Nordstream, if you do not accept our landsteal in Ukraine, the same could happen to oil pipelines of yours."
The Russians have submarines equipped for detecting and in any way manipulating transatlantic cables, pipelines and such. It was reported already years ago.
I would give the US theory more probability if it were not Biden but Trump still being in the WH. As a matter of fact, Biden is more Europe-friendly (which does not mean he is Europe-friendly, he only is less Europe-hostile than Trump and less Europe- indifferent than Obama were, but Biden is America-first in all regards. Still it was him who saved the Germans from punishing US sanctions over Nordstream 2 last year. What he maybe regrets now...).