I fool with dogs a lot, do a lot of bitework with police/military type dogs. Most of these are pretty social, with a protective edge. I wouldn’t trust a chow, ever, unpredictable and not very intelligent, which is a bad combination.
I loved Merlin, but when he snapped at my son, I couldn't take the risk.
We have another black lab, a female. Thinking about getting a puppy, but I would not buy another chow.
I think German Shepherds are very intelligent.
Anyway, as you say, unpredictable and not intelligent. Not good.
Your job sounds interesting. :)