Unfortunately, that is his best chance. You want him to box? Show me one match where Jacobs shows superior boxing skills.
GGG grew up fighting in the streets. He was a club bouncer as a teenager. Stree fighting against him as good an idea as hiring Bill Cosby as the barender for your daughter's 18th bday party
If he goes all out and makes it a street fight, he gets KO'd quicker, so no, although if he attempts to outbox GGG he gets outboxed and TKO'd late and if he plays it hyper defensive and tries to survive, he'll be walked down and KO'd, he's screwed no matter what he does.
It cracks me up that people think that there isn't a chance Gennady himself could be knocked out in this fight. There's this near consenus misdirection in discussions about this match that somehow Gennady isn't vulnerable to blindly walking into a perfect counter shot from an elite world class fighter. At the level they're fighting at anyone can be knocked out. Two guys at the very top of the heap. All it takes is one. Jacobs is a nuclear puncher himself. He doesn't pitty pat guys over the course of 10 rounds and get mercy stoppages, he has that power where he disconnects fighters from reality. Watch him put the super tough Giovanni Lorenzo flat onto his face and out with one shot. He's got Andy Lee esque displays of power but certainly doesn't get the love Andy did a few years ago.
Jacobs chin is too poor to hold up in a boxing match against a super puncher like GGG If I were on his team I would say go out and get him Kill or be killed, Jacobs is a monster puncher himself so if he gets in first he can have good shot.