I’ve had great success with CBD for my anxious dog. It makes him a little spacey if I give him too much, but in small amounts it does an excellent job. You can find tinctures made with dogs in mind that also taste good to them. I’d either put some on his food or directly into his mouth.
We haven’t used it in a while, and I do not remember the brand. We found a local smoke shop with a very knowledgeable owner who sold dog specific tinctures. Finding something local is usually a great bet if possible.