Given the rise of anarchists and fascists in Europe (especially Greece), hostilities between China and Taiwan and China and Japan, the Korean Peninsula, the Ukrainean invasion, and more problems in the Middle East to count (including Iran, CIA, and Israel/Palestine), and the Kashmir, how will World War III start?
I don't think any of those will cause WW3.
Sure, there's tribals in Europe, but they aren't organizing some kind of mass imperialistic campaign to take over the world. Essentially that's what got national socialist Germany into WWII, not necessarily the fact that they were committing genocide.
The conflict between China and Taiwan doesn't really have the propensity to become a 'world war' because there just aren't enough major powers that would be willing to fight China for Taiwan. For instance, the United States is probably never going to be at war with China just because our economies are so interlinked. It would screw us both so bad that peace is just a cheaper option.
As for Ukraine, I would rate that as the most likely cause of the next World War, but I don't think it's actually going to cause one. The United States doesn't seem to have any vested interest in sending over military powers to defend Ukraine's sovereignty. We're handling the situation by sanctioning the forget out of Russia, which just goes to show that economic solutions are cheaper than military ones.