I thought the border restriction was just about having been in China in the last 14 days. Couldn't she get back into the US if she went to a different country first for 14 days?
No. The U.S. refuses to even process visas. Early on, the U.S. initially held her passport (a foreign one at that!) for over a month, preventing travel to countries she had valid visas to. When she eventually did once the passport was returned, the U.S. canceled her appointment, forcing travel back to China. Such foreign visas have now expired. The U.S. continues to allow appointments to be made at embassies and consulates and then cancels them right before. She actually falls into one of the conditional allowances that should get her back, based upon lawsuits from large employers, but the U.S. is not keeping appointments and not processing visas. So whatever they claim is allowed (which is not much), they are blocking that and more on a procedural level, just like they were doing since January before any bans were even in place. They don’t care.
H1Bs and others (at least from China) are banned at a minimum until January 2021.
We are in a similar situation. She’s got a tourist visa though, and while we think it would technically be possible for her to enter the US, we’re kind of afraid to try.