I have a 2 year old gsd who’s high driven for a ball, but he isn’t much interested in biting the bitepillow, he will bite it but will let go. Seems to me he isn’t really interested in it. Any training methods to build drive?
I use a variety of toys: shape, material and weight from the very start for fetching and tug after one dog (years, years ago) only would fetch balls because that's the only toy I used to play with him. Not sure if that matters though regarding possession and drive.
In the meantime or if you don’t have the said resources in your area, a flirt pole can help... also, during your tug sessions - allow him to win, A LOT! He’ll likely accept a rag over a pillow at this point too.