Food and Toy driven are for a reward system
Odor is everything to a dog even with low hunting drives. Some dogs thrive on finding things with their nose. Dogs for SAR are selected, in part, for their desire to hunt for an odor in the absence of visual stimuli but they must have a strong toy(preferable) or food drive to shape it into something useful.
It sounds like your dog might enjoy tracking. or maybe nosework. Maybe there is a club near you. AKC tracking does not require you to get involved in obedience/protection as does schutzhund and is very fun. There are folks on the forum involved in nosework which is similar to the detection work police and cadaver dogs do.
I would not suggest search and rescue given his reactivity and apparent low toy/food drive.
NAPWDA Certified Cadaver Dog
Waiting at the Bridge (italics
=GSDs) (hemangiosarcoma=blue):Grim , Cyra, Toby
, Rainbow, Linus, Oscar
, Arlo & Waggles