The self-report objection has been tested, though. Aphantasics show no imagery priming in binocular rivalry, no pupil constriction when asked to imagine bright shapes, and flat skin conductance to frightening text while responding normally to frightening pictures. A questionnaire that predicts autonomic responses nobody can fake is doing more than semantics.
Yes, sorry I believe we are saying the same thing.
I'm saying there are a number of physical tests like the ones you describe, and those line up with the much simpler apple imagery self-report test.