Hello Libman,
Okay, my journey has been very looong
For me the key was raw milk kefir, with the kefir grains. It will mend most of it. Take care not to drink too much. It will create mineral imbalances (too much calcium, too little magnesium)
AV followers will tell you that kefir grains are bad and to spit(saliva) into the milk. Don't do that. Impossible to expect repopulating bacteria strains missing in your gut when culturing with your own saliva, right?
High meat is equivalent to this, but there are no grains taking care of the process so I wouldn't use it. But I think it can be very beneficial and even better than kefir.
If you have IBS you'll have low stomach acid for sure. Don't eat meat/fish that can contain parasites or it doesn't smell good, avoid it or cook it. Yeah I know this is RPDforum, but you have to transition. A veteran raw fooder has strong stomach acid and a good microbiome that will be unsuitable for opportunistic microorganisms.
Ruminant raw muscle meat is safe almost always.
If you eat plenty of animal protein you won't be hungry. Then fast. When breaking the fast you might experience diarrhea, you'll expulse biofilms, that's good.
Your strategy has to be not feeding your dysbiosis, that's why protein and fats are good, because they don't ferment as opposed to fiber. Paradoxically, it's better for you to eat cooked meat rather than raw vegetables.
I am able to drink nut milk, I crush it with a mortar and pestle and then use a cloth strainer. The solids go to the trash.
Eggs for me were a major trigger. Think about it, they are not fresh at all, they might be 4 days old. Now if I drink an egg shake I add some kefir always. That somehow does the trick.
It' a long time I barely drink plain water. Broth, kefir, electrolyte powder etc.
Fructose is also problematic. Starch itself doesn't trigger strong reactions but it keeps feeding that dysbiosis.
So a low carb diet is optimal. Try to get fatty meats, the fat in the muscle it's much easier too digest than say, suet.
If you need carbs go for fermented starch or use vinegar to avoid weakening stomach acid.
Good luck.
