It could start anywhere. In your neighborhood.
The author is deluded, and is a ilberal anti-Trump partisan. His focus on liberal talking points steers him to false conclusions.
As you say, a hot spot could flare up anywhere. A conflict in Africa could mushroom into WWIII, with major powers squaring off against each other (China is going all in, in Africa). The European Union could splinter, as EU countries against further immigration from Africa and the ME go against Germany and other countries, and could pull in major powers and spiral out of control. It's not going to be Taiwan or Ukraine or Turkey. The major ones are NK and The Gulf. Those two are the most likely to explode out of control, and it won't be because of President Trump despite what the author thinks.