This was just our experience, on the 19th. I would say, YMMV. As with everything here, who knows how it would have been handled by a different immigration officer. This was our 1st entry in the covid era, and quite a bit different from entering Vietnam, a month earlier
Well, I didn't have my insurance document printed out, and we were taken aside because of that. Had it in pdf on phone & laptop. Took them a bit, but they printed a copy. Then he escorted us back to the immigration desk. That's when the issue of no reservation past the test & go came up. But, after I said we didn't know if we'd be quarantined, and were going to stay at the same hotel, it was no problem. (YMMV)
We entered 12 days ago. Just had the 1 night T&G reservation. Immigration wasn't happy with that. I said we have no future reservations because we didn't know if we'd be kept in quarantine. I said if we're released, we'll stay at same hotel until we find condo.
To expand, the IOM Vietnam helped my fiance with the visa application process - interview, any forms she needed to fill, and getting a flight to the US, navigating through immigration in the US.
Our experience with said 'bs feeder company' over the last 6+ years living and bouncing around S.E.Asia has been the same - very good. And saved us money too.