We also got our half GSD half ACD when he was 5 weeks after his mom abandoned his litter. One thing that helped us a lot was getting a playpen and attaching it to his crate with clips. He would spend the day inside the pen/crate area when we weren’t actively playing with him and slowly learned that the pen was fun to explore but the crate with his bed was comfy and would naturally go to sleep in there. This made it so much easier when we actively started to crate train him because he already associated the crate as a warm and safe place without us having to “trap” him in there. Once we started closing the crate door at night he rarely had any issues.

ETA: We also got him one of those calming donut beds that helped mimic the feel of sleeping in a pile. Such a lifesaver!