A very interesting article in the New York Times (link should bypass paywall) about totally virtual online marriages being performed in the state of Utah, USA:
nytimes..com/2021/09/17/style/utah-county-weddings-virtual-unlocked_article
It does mention that many jurisdictions don't consider these to be legal marriages if the marriage has never been consummated.
Having said that, obvious questions for this forum are,
"Would Vietnam recognize such a certificate for a spousal TRC (after borders open, of course)?"
and,
"Would embassies (especially the US Embassy/Consulate) recognize it for a spousal Visa for the Vietnamese citizen to travel abroad (once international flights resume, of course)?"
Asking for a friend...