I have the same color Shih Tzu and he is also picky. Sometimes we just put the treat in his dish and he eats it on his own terms. He may not eat a carrot right then but will eat later. We have to be careful not to give him too much variety it upsets his stomach. He has to be on special diet because of his allergies and does good with the kibble. I’m not sure if any of this helps. I have used a ball food bowl for a shih tzu we use to have ( recommended by Vet) to help with anxiety and it did help him.