Answer:
I believe that the two most important reasons for the US trade deficit are:
The US is the largest economy in the world and the dollar is a currency that is accepted virtually everywhere. A solid economy (reason #1) plus a strong dollar (reason #2) results in many goods purchased by Americans. Until the beginning of 2020, the US economy had been growing for more than 11 years in a continuous manner. Such long economic expansions are not common, and they clearly show that the US's economy was healthy (at least until 2019 ended).