You’re right, there are people that assume that bad hips automatically = sloped back (it isn’t, those crooked looking dogs hips are tested before breeding in Germany) and good hips = straight back, that’s incorrect and that’s why health testing should really be done before a dog is bred, though environmental issues can contribute as well.
His breeder guarantees the pups for hips provided you have an x-ray done at age 2.
My little girl who is 2, came from a back yard breeder (but AKC) and we have had no reason to have her x-rayed for anything. I am not going to breed her so I have to go with my instincts that she is good. Fast runner, not injury prone.
Neither one has a sloping back.