Rolling the dice isn't enough reason to go to war these days. Because you could lose everything.
Looks like, that the Russians consider possible militarisation of Ukraine as an existential treat. So, they prefer to start a war against Ukraine (or whole NATO) and have good chances to win it, than allow the USA prepare for a war on the American terms.
So, there are list of scenarios from the safest to most risky:
1. NATO fulfil terms of NATO-Russia Pact obligation and withdraw forces from the Eastern Europe - 99% chances of peace, win-win situation.
2. A war against Ukraine on Russian terms (NATO countries are really neutral) - 95% Russia wins in few weeks without significant losses but lost money and time on rebuilding of Ukraine.
3. A limited nuclear war in Europe (the USA neutral) - 90% Russia wins, but then get stuck in the European mess for a long time, and can't make money in Pacific region.
4. A nuclear war against the USA on Russian terms, the USA consider Russian preparations to the attack as 'bluff' and 'a mere psychological war' - 70% Russia wins without significant losses, 25% - Russia wins with significant, but acceptable losses.
5. The USA continues militarisation of Ukraine and the Eastern Europe, NATO attack Russia on American terms - 100% there will be significant (tens of millions) Russia's losses, chances to win 50/50 even with a significant help from SOC countries.
The fifth option is totally unacceptable for the Russians, the first one - most acceptable for the Russians, but looks like not acceptable for some NATO leaders. All other options are on the table.