He struggled shooting
Keyonte George, by any metric, was a bad shooter during his campaign. While you can look at his per-game box scores and see 13 points, over four assists, and nearly three rebounds, look beyond that. Look at the efficiency of George, because it's not there. His standard stats are bad, he shot under 40% from the floor, barely over 30% from three and while his free throw stats were fine (84.8%), it tells a tale of a guy who can't shoot the ball. In the modern NBA, that's a problem.
But let's say that's not much to write home about, his advanced stats are even worse. His true shooting stats are below league average, at just 53.3%. He's not making the shots he needs to make and he's struggling to hit shots he shouldn't be taking.
Now the issue is consistency. On some nights he'll go nearly perfect from three-point range, but on other nights he can't hit a layup. So is this an issue of talent or consistency? It's far more likely his best games are the outlier and not the other way around, but it is still too early in his career to say either way.