I think the biggest surprise will be that the next big war won't happen.
Prior to the end of WW2 major powers were in a semi regular state of conflict typically with each other. Since the end of WW2 no major powers have been at war with each other. Major powers have been at war with weaker powers and there have of course been civil wars, cold wars and colonial wars. But colonial wars have now practically ended and civil wars tend to end sooner and have longer lasting peace treaties with the involvement of the UN.
Of course if you turn on your TV you'll think that the world is off to hell in a handbasket, but the data shows that war is becoming less frequent and with less casualties despite the increase in firepower. You can add up all of the conflict deaths between 1946 and 2020 and you still won't get anywhere near the number of people killed by war between 1939 and 1945.
No major power has been at war with another major power in 75 years and whilst this may seem normal to our generation, this is perhaps one of the longest periods of 'peace' ever experienced by human society. Now people will cite the regular terrorist attacks, Iraq war, Syrian War, Afghanistan War, Vietnam War etc as evidence that we are not in a state of peace. But to those I say look at history, wars between major powers used to be the norm and I'd personally rather live through a period with terrorist attacks than through a period where I find my country at war with Russia.
Countries now are more interdependent and intertwined with each other than ever before. Collaborations on multiple projects span across nations and the huge increase in intergovernmental organisations since the end of WW2 help foster this collaboration. There are more democracies than ever before and democracies tend not to go to war with each other. Trade is global, communication is global, the threat of nuclear annihilation is global. The use of war as a tool to exert power or to solve a disagreement between major powers isn't an attractive an option as it used to be in past centuries. There are now less risky options available and non-biased organisations that provide alternative avenues to resolve conflict that were just not present in previous conflicts.
I don't think we've seen the end of war, but I think we perhaps have seen the end of wars between major powers. And if you don't agree with me then you might want to at least hope I am right