Bagley's lack of right hand and ability to drive right is really, really, really hurting him in the NBA. Let's put it this way....
Bagley has elite athleticism. Quickness, hops, speed, you name it. However, when he faces up, his defender can neutralize his athleticism advantage since he can easily anticipate which direction he is going to go. (e.g., how do you beat someone faster than you? Take off before them).
Because the defender knows which direction he's going, he can also close the gap between him & Bagley making it harder to shoot. He would be centered on Bagley's left shoulder allowing him to easily contest a jumper while feeling very comfortable about keeping up with him once he goes left.
Developing a better jumpshot won't be enough because the defender can easily take that away by closing the gap and opening up his body to Bagley's right. Bagley would still have the same issues he has now.
Bagley priority needs to be improving his finishing with his right hand and dribbling/driving to the right with his right hand. If Bagley makes it to where the defender truly doesn't know what direction he is going to go, the defender will need to sag off of him because there are very few who can keep up with his athleticism.
At this point, Bagley would then need to work on the jumper so when his defender gives him space due to his ability to drive left and right, he can punish them by making the jump shot.
He's got a lot of work to get there, but I feel better that I can at least formulate a path for him to become great on offense.