Both China and the US do not recognize Taiwan as an independent nation
Taiwan feels like one of those cases where a little ambiguity is actually safer for all concerned than a clear position. You ideally want a situation where the mainland can saber rattle occasionally to keep their domestic audience happy and where Taiwan can sometimes make it sound like an independent state, but neither moves down the track any further.
An invasion attempt by China or a unilateral independence motion by Taiwan would be a disaster for all three parties, the Taiwanese, mainland China and the US.