Worse than cancer is the complete lack of dietary fiber. And no you cannot reset the gut microbiome on a carnivore diet by supplementing with probiotics and expect the same result.
What is the first part of a kill big cat carnivores (including cheetah) eat? It is bowels of herbivores, full of plant matter.
“Worse than cancer is the complete lack of dietary fiber.”
Why do you think that is a problem?