Better or worse, little of what the executive does is really because of the president directly. The president chooses the sort of people to put in positions of power then the whole ship largely sorts itself out. But the president gets to be responsible for everything because they are nominally in charge, and people keep pretending they are superheros with all sorts of ability to personally oversee how the US operates.

We can certainly say that if Trump didn't want quantum computing research to happen his administration wouldn't be doing it. So if it does, he has de facto supported it. Even if by inaction.