A population of cloned dogs wouldn’t neccesarily have the same sort of genetic weaknesses that a population of highly inbred dogs would. Breeding a dog with close cousins/siblings brings out recessive traits that are disproportionately seen in inbred vs. outbred/hybrid populations, but cloned dogs wouldn’t neccesarily have those. As far as susceptibility to disease, if a bacteria/virus were able to evolve to explot a genetic weakness in a cloned dog, all that dog’s clones would have the same weakness. Developing cloning technology could help preserve varying varieties and pedigrees of dogs, in the same way seed banks help preserve botanical diversity.