Mixed Dog I plan on adopting in 3 months

His name is Xiao Le (means little deer) and they think he is a German shepard mix. He was found as a stray and his age is unknown (Presumably 5-7yo, he came to the shelter in 2021 so hes lived there since he was a puppy).

As for temper, hes very relaxed but will snap at other dogs if they annoy him too much but never bites or attacks. He has a habit of standing between my legs but faces the opposite direction. He has a short coat that sheds a lot and hardly ever barks. I don't know how heavy he is but he is about the size of a German Shepard.

Any ideas whay breed he could be and what health conditions to watch out for with said breed?

Taipei, Taiwan