Edit: I done messed up and confused strategic ambiguity with other ambiguity re. the status of the One China Policy in recent times. Thanks to immuredanchorite for the correction.
The White House does not recognise the PRC as the only China though, they adhere to the One China Policy which acknowledges the status quo of competing claims by the PRC and ROC over Chinese territory and Taiwan province.
Them backtracking Biden’s gaffes wrt the status of Taiwan as a country is only to retreat to the ambiguous ground of ‘One China’ they currently operate under.
(honestly, I’m not entirely sure I’ve even gotten it correct in terms of how the USA defines its One China Policy because they deliberately keep it vague to allow themselves maximum freedom to engage with the ROC as though it were a sovereign government. All I know is they wouldn’t go so far as to say the PRC is the only China, that would be seen as too much of an endorsement of the PRC’s own ‘One China’ policy vis territorial integrity and governance)
I could be wrong, but you might be confusing this with “strategic ambiguity” which afaik is keeping the PRC and ROC both guessing about how far the US will take its intervention. The “one china policy” wasn’t ambiguous, it was a necessary step in order to create normal diplomatic relationships with the PRC. But once the US had normalized diplomatic relations with the PRC, it effectively said, “There is only one chain and the PRC is the legitimate government that we formally acknowledge.” That is why all of these recent state visits between politicians in the US and Taiwan is so inflammatory. The US is only supposed to have “unofficial” ties to any other “government” that is supposed to represent China.