One of the major issues is that IQ has basically no cardinality to my understanding. We can all agree that 105 score is "smarter" than a 100, but we cannot disc

One of the major issues is that IQ has basically no cardinality to my understanding. We can all agree that 105 score is "smarter" than a 100, but we cannot discern to what degree. I've read some conjectures that IQ is quite accurate below average, but seems to fall apart rather quickly the further one starts looking at scores above 100. But who knows? I'm just some random dude with Internet access.