Global capitalism is what was in place before world war one. It is no cast iron guarantee. There are ways where capitalism and war align.
WW1 had nothing to do with capitalism.
It started at imperial era, when waging wars to move borders was a routine.
Germans felt bad about not having the room to expand, despite having strong industry and quite an army and fleet.
WW2 was the guys who lost WW1 giving it another try.
After that try countries agreed on never moving borders by force again.
What Ruzza and Putler are doing (the f*ck is driven by the butthurt from losing the Cold War, quite like Hitler had BH from WW1, except German WW1 defeat was way more humiliating), if successful, will bring us back into that imperial times. With unpredictable results.
I do NOT believe US would get directly involved if Xi decides to grab Taiwan, which, mind you, is part of People's Republic of China de jure.
I don't see why Putler would stop trying to expand, unless his ass is kicked in major military ways. I hope Collective West gets that before poor Ukrainians bleed out dry.