I'm going to make some generalization on this so take it with a grain of salt. I think there are ample cases of big, strong passers -- kids that grew considerably before age 18 -- versus smaller types like Trace McSorley and Alabama's QB.
The bigger, stronger armed pro-style quarterbacks are often late bloomers. I think of Will Levis, who is now a first round pick. Huge improvement in him from just two years ago. I think of Tom Brady. Some, like Hackenberg, do not pan out. Christian in my opinion never was able to make the shorter touch throws. Allar is already able to make all of the throws. We've seen this. We've seen some overthrows, but as long as he gets protection, that will work itself out. The staff should never let their QB start throwing off the back foot no matter the pressure.
Another quarterback that no one mentions is Christian Veilleux, who just entered the portal, as I would have expected. He seems to be on a Levis trajectory. Huge improvement (to my eye) in the limited action we saw of him this year relative to the past. Whether he turns into a Levis-like leader is another question. Very disappointed to lose him but this is what we can expect going forward. No one will have a great backup. Teams must now forget about running the QB, concentrate on pass protection, and make sure their starter doesn't get hurt. I'm good with this as it brings the kind of football I want to see.
I think the smaller, four year high-school starter QBs a la McSorley plateau earlier. If they are used as a runner they get banged up, just as Trace got banged up. Same with some of OSU's QBs, which is why they are turning to more of a pro-style attack as well. No one can afford to lose their starter.