I squeak a toy and get him interested, then I show him me putting it into a box (usually one a delivery has come in but cereal boxes work too) and then he goes nuts trying to get it out.
Also I know you said he is not food orientated but mine loves nothing more than if I put a high value treat into one of his large stuffed toys (show him you doing this) and say Oh what a naughty bear eating one of your treats and now it's in his tummy and then the dog goes mad ripping the toy apart to get the treat out.
I also have him giant stuffed bear type toys and he likes to hump it, throw it about and pull it's stuffing out. He will play with the giant toys on his own but not his smaller toys.
Also still food but mine loves these activity books you get. Look on etsy at the Pet London shop and they have these activity books where each page has places to hide treats. I found these work well to keep my dog busy for up to 20 mins. It seems to work better than the activity games. The Happy Birthday book is good and so is the Laundry one.
Anyway I feel your pain. My dog is only small but I am constantly trying to keep him busy.
We have just had 'find the treat' when I break up a large treat and hide it under cushions, rugs, etc and he has to go round and find them. He loves doing that.
Finally make sure he can see out of a window so he look at passing dogs, people, squirrels, cats etc. Mine used to spend hours doing this although we live somewhere not with less passing traffic so not so interesting.
It's weird but the more difficult I make it to get the treat, the more interested he is in having it. Handing him the treat is far less interesting.
P.S. My dog loves the 'cats and dogs' movie so I sometimes put it on for him and he will watch it for about 20 mins before he gets bored.