Why now? I think that the bitterness toward Russia in Ukraine is so extreme right now that Ukraine would cut of their nose to spite the Russians. I also think that some feel this decrease in natural gas to Europe along with diminished revenues to Russia, might help Trump broker a deal to end or pause the war between Russia and Ukraine.
Trump has nothing to put on table, Russia is aware that it was going to happen and is diverting trade to China, China is reducing imports from the US at the same time.