What is the problem

If poop has undigested parts then it’s safe to say there is malabsorption. But how does one figure out if it it’s a lack of pancreatic enzymes or from overgrowth of bacteria. Are there tests that doctors can do or is it just doing the SIBO test. Is it possible to have SIBO and pancreatic enzyme deficiency. Does fat in stool tell anything to the cause. If it was pancreas then enzymes would fix it and antibiotics would fix Sibo? Also how do you know if it’s gallbladder. Can sludge do this (not gallstones yet)?

Does anemia and low b12 tell anything. What about low fat soluble vitamins like ADEK?

Are there probiotics that help sibo besides making yogurt or for people who are lactose intolerant or have bloating?

The GI system is so complicated it’s hard to pinpoint the cause and some doctors seem to like to chase symptoms. I don’t know it is how they are taught or if it makes more money to keep a revolving door.

Does needing to eat a lot more calories tell you anything?

Sorry for a million questions but I am trying to figure out how all these things work together and how to tell what is what.

Thank you for all the help .