You seem to be missing a few facts. One is that an individual can have both ADHD and NPD, and that the rates of NPD are actually higher among those with ADHD than in the general population.

Two, if you don't see Trump fidgeting, if you don't see him walking around when others are standing still for a photo-op, if you aren't counting the excess head bobs, torso twists, and movements when he talks, you're simply not looking. I've actually counted body movements, and in debates he is way off the charts compared to his peers.

You also seem to have not understood that narcissism is about content of what he says and does, and ADHD is about process.

He unequivocally fits the current definition of ADHD, and I have heard hundreds of individuals with ADHD, and many experts on ADHD concur with that assessment. Whether it is being exacerbated by dementia, seems likely, but is harder to verify without biological markers.