on Most logical levels Russia starting this war with NATO nations through Ukraine is suicidal for Russia and maybe China too

 Why?

Because autocratic nations cannot get their people behind them really unless it is by starving them and making them slaves and not feeding them as a way to force them to join their armies so they will get food.

So, the makings of the end of both Russia and China is in Global Climate Changes. That's not to say that the U.S. couldn't also be undone as a nation if Trump or another one like him comes to power either.

So, at this point in world history, Russia, China and the U.S. could all easily cease to exist as nations or be bombed out of existence (all of them) by present weapons available for use. no new ones need to be developed to end all life on earth as of right now.

For example, the U.S. is presently developing "Doomsday Weapons" that would kill everything living on earth if the U.S. got nuked and we already had stuff like this since the 1950s and 1960s along with every other nuclear armed nation like Russia, China, Pakistan, England, France, Germany, Israel, India, North Korea etc. etc. etc.

And it is also quite likely that Japan and Saudi Arabia also have nuclear weapons and doomsday weapons in place as well.

So, if the human race doesn't go extinct from global warming it might also go extinct from nuclear or doomsday weapons anyway.