What I am most worried about the governments spending much monies on weapons is that the government would find all means to acquire weapons just to fight a war but could not find solution to fight human needs in cases of educations, hospitalities and creating better economy levels to suit the masses.
Some nations that are financing these wars have huge debt threatening their financial stability. But because they have other evil intentions, they are willing to use taxpayers' money to finance wars instead of channelling it to developmental purposes.
There is no doubt that humanity is doomed and it is only a matter of time because of human greed. But about World War 3, I don't think it will happen soon or it will be a nuclear war like many people are imagining. I believe that war in the modern world will be economic war, biological war (disease, pandemic...) and they will be more unpredictable than physical war.
Israel and its allies seem to have the freedom to kill at will. The UN has proved that it is powerless. So I doubt if the conflict will lead to a world war. I don't think the West will approve Ukraine's appeal to use long-range missiles against Russia. If such approval is given, Russia's reaction will determine if there will be another global war.