hobby don't matter
If you want to call it hobby.
As long as he is acting successfully in the interest of the US
He isn't.
The most important edge that the USA had over China was the worldwide net of close alliances with highly developed, high technology, heavyweights - Japan, South Korea, Europe, Canada, Taiwan. He started his term from threatening Canada with annexation, makes a complete mess of coordinating foreign policies against China with Japan and South Korea, totally alienated Europe, and even tells Taiwan that they don't spend enough on defence and perhaps may not count on America's help lol xD
In other words, he is busy dismantling America's greatest advantage ever, that took them over a 100 years to build. But - on the bright side - at least he's economically illiterate.