Ya this is unsettling. I remember me being one of the people telling you a while back that "oh puppy tummies can be unstable and just wait it out, it should settle". This doesn't seem like that anymore. I agree with
@Ravenbird on the liver/thyroid tests, Dobies (i have read) often have thyroid stuff going on? I feel for you, it's just so hard to watch when they don't feel well and they don't have words to tell us what it's like.
Maybe a partial bird could do it?
Other than the vet's help, the only thing I can think of, and maybe you're already doing it, is a probiotic, like every day of her life probiotic (even if it's raw goat's milk or whatever). the other thing I wonder is if you give her a monthly oral flea/tick/heartworm preventative? My dogs all pooped puddles after their first dose of Nexgard plus? I don't know I am just grabbing at straws, I admit. Something is going on with your poor Pepper and I hope you can learn what it is soon!
I'm really glad she's hungry though.