There are some logical fallacies in your arguments.
Covid19 has not stopped most imports/exports in areas were good still exists, some goods are limited/not available but this is not due to trade route disruption so much as manufacturing disruption in the supply chain. Some areas like oil import have caused futures traders to lose cash due to the overstock of oil.
While tourism can/will be impacted by countries with active Covid19 cases for most countries tourism export (those coming to the country) is a very small part of the tourist industry and an even smaller part of a countries GDP. (the industry is 2.8% of the USA GDP, International Tourism accounts for 32% of the total tourism industry) https://travel.trade.gov/outreachpages/download_data_table/Fast_Facts_2017.pdf
So even if no tourist from outside the country came over it would have a small impact on the overall GDP of the USA. Changing the overall countries policy in regard to the current pandemic would not change the country's foreign trade nor lead to a countries attempt at being autarkic. In fact, the two countries you listed as being simi autarkic are not of their own choices but forced upon them by sanctions by the UN. (North Korea still trades heavily with China, Venezuela top three trade partners are USA, China, and India)
Dumping of treasury bonds would hurt the holders of the bonds just as much as it would the US. Of the 22 trillion issued 36% is held by the US Government, 28% is held by foreign countries of that percent China holds 17.3% and Japan holds 16.5%. https://www.visualcapitalist.com/foreign-countries-holding-most-u-s-debt/
Economics has maintained that the overseas demand for the dollar has allowed the US to continue a large trade deficit while not affecting the value of the dollar or cause the trade flow to readjust. But that in the near future these pressures would precipitate a run against the US dollar with serious global financial consequences and a rebalancing of the US trade.
So no the country going back to work would do far more to stabilize the countries economics than the possible loss from tourism. In fact, going back to work now would help establish goods and services that currently are not being met by other countries thus increasing exports and further strengthen the dollar.
