Possible, but wont happen. No one need that that war, as no one will win in it. It will be a destruction for everyone. This Russian-Ukrainian conflict was running for ages and will continue to run. For WW3 to happen, Russia must start invasion of other countries, or other countries must send their troops to Ukraine territory and they must have been attacked by Russia. Does Russia have similar conflict with other close countries - no. Does other country military can do a significant problems to Russian military - yes and no, as no one in clear mind wont try to involve that deep in Russia-Ukrain conflict. I expect more and more severe sanctions against Russia, world wide price growth, but not WW3.
NATO rejected to send army forces to Ukraine. They don't want to stuck there and Ukraine is not an official member of NATO. Putin just want to break the chance to join NATO of Ukraine. He is smart enough to know that if he invade Ukraine and want to merge this nation to Russia, the hell is waiting for him and his nation.
World War III will appear if he does it but as said, I think Lutin does not want it.
About Bitcoin, it does not fall because of Ukraine-Russia war. It will rise because of the geopolitical confict or the war. Just like it crashed because of the pandemic announcement in March 2020 then rose and made its alltime high because of consequent inflation from the pandemic.