No.
His arm length isn't really a big deal IMO because he's a power to speed rusher, which means the #1 tool that he'll utilize is contact initiation. He's not try to just run past OT's, his first move is to initiate contact to knock the OT off balance & then uses his speed to get to the QB.
If he were purely a speed rusher, then yes arm length would be more important.
2nd, neither one will be necessarily ready day 1, because we already have multiple DE's that will be playing ahead of them by the time either one gets on campus, so neither one would be expected to start as TF's.
Also, they're 2 different positions. One is a Strong Side DE & the other is a Weak Side.
Bryant is a 3-Out/4-In/4-Out rusher, while Jacobs is a 5-Out/6- through 9 rusher.