The first thing to point out is the numbers themselves. Tre has a very low rim rate and free throw rate. That is something a highlight video can't tell you and also can't dispute. But ironically, Tre's highlight videos do show a lot of instances where he doesn't get all the way to the rim. A big reason why he has so many highlight pull up jumpers is because he's unable to beat him off the dribble.
Your point about them being obsessed with pull up jumpers, that's absolutely part of the problem. Both of them have to answer the question of whether or how much their lack of rim pressure is because they can't get there or don't want to get. It's a combination of both, but you could debate how they fit onto that scale. If you think it's more of their mentality and not ability, you have to address the question of how much they are willing to change.
What we do know now is that their current shot distribution makes it hard for them to be efficient. The best NBA players usually efficient because they both make tough shots and also create easy shots for themselves. Historically, rim rate and free throw rate does not improve in the pros and you rarely ever see a player go from low to above average. This is my concern with these two. It's already low, and history shows that it almost always stays low and/or gets lower.
As far as the Fears comparison, I really don't want to get into the weeds about that for something this broad. I just brought up two SEC players because if you're going to use that excuse Tre, you need to be consistent about giving that grace to everyone. You can point out minute differences between SEC teams, but it doesn't change the larger point that rim pressure does not get easier in the NBA. The idea that rim pressure will get better because of the difficulty of a conference or poor quality of teammates just doesn't hold a lot of water.
