How is Russia-Ukraine war relates to that? Is it even a war (neither Russia nor Ukraine declared a war officially)?

USA works for many years on destroying German industry. Starting from not allowing to build gas pipelines from Russia to Germany and eventually destroying them (I don't think that even brainwashed western population believes in that bullshit theory that 5 guys on a yacht destroyed Nord Stream). To the Volkswagen emissions scandal and plundering Deutsche Bank.

Russia always wanted to be a friend with Germany because that would be highly beneficial to both parties. USA always looked for a way to make that never happen and to destroy German industry.

USA succeeded, Germany has a bleak future ahead. But that is only tangentially related to energy import/export.