Chase is great... if he's chasing you. But if you're chasing him, this is very bad.
Playing chase, with him chasing you, will also help with engagement. Play chase with food.
Also, I would recommend hand-feeding for (at least) a month. You want to build value in you.
In addition, it has to be said, that some puppies are just lazy and like being bummy. You can encourage active behavior by making yourself valuable (so he wants to be around you) and by making activities valuable. At 6 months however, you might be out of luck. Still, it's your dog, so it's probably worth it to give it a dedicated try.
You also, might want to try using more valuable food rewards (like steak, cheese, etc. (whatever he loves and doesn't typically get much of)).
Best of luck.
