he wears a choke collar up behind his ears and is rewarded periodically (for best efforts) with treats. He will do all the basic AKC OB exercises, and has more animation if he knows you have his Kong, which he LOVES. I do collar correct if needed, but it's not often. Sometimes heeling he'll need one, but is rewarded when he's right.
Okay, ditch the treats and use the Kong for a reward, and not just intermittently. You want to use whatever reward motivates him most, and use it frequently. For now, just to get his motivation and attitude up, throw his kong EVERY time he does something right. Later you can reward him every second or third time, but for now, you want it to be a game of fetch with some obedience thrown in.
Try to approach things this way: pretend HE is the one training YOU... to throw his kong.
Get him excited with the kong, then give him a command. As soon as he obeys it, throw the kong.
When heeling, put the kong under your armpit. When he's looking animated and happy during heeling, and he's in precisely the right position, throw the kong.
Ditch any corrections, either by stern tones or by collar, for now. If he does not obey or perform correctly, he doesn't get his kong. That is his "punishment". Keep it positive and fun for him. You can add corrections later, if needed, but for now what you are doing is re-wiring his brain so that he feels differently about obedience and about you.
Pretty soon his mind will switch over from following commands out of rote with few rewards, to pushing you for a reward, by performing the action he knows will make you do it. Like he is training you.
Keep training sessions short, happy, and energetic. When you see his energy or drive flagging, stop the obedience and just play fetch for a few throws. Then give him some water, and put him in his crate for 20 minutes (or more). No scientific studies have been done to prove that crating a dog after a training session helps things sink in, but many trainers recommend it. My theory is that it helps the new associations and connections form while the dog is in a state of sensory calm, without any influence from other things that may be happening around him.
I assume you are the one who feeds, walks, and grooms him? If not, become that person.
Working with soft dogs can be a challenge.
Is there a Schutzhund club in your area? If so, see if you can join for the obedience part, or at least watch others doing obedience. SchH people have great methods for happy, animated obedience.