@Notjustfatigue Something I've come across recently that might be worth a try first if diarrhea is an issue is a xyloglucan product. Or maybe it could even be used as an adjunct to FMT
Xyloglucan is a film-forming protein based mucoprotectant that puts a liner on the intestinal mucosal layer which is then said to improve the intestinal mucosa resistance to pathologic damage. It's only marketed in Europe by the looks of things and was previously only promoted as an anti-diarrheal product, starting out as gelatin tannate before adding xyloglucan to it and now it's being promoted as an IBS treatment.
Anything that might stop or reduce intestinal permeability could go a long way to moderating symptoms regardless.
One paper said of this;
https://www.tandfonline.com/doi/abs/10.1080/17474124.2018.1378573
[Xyloglucan is a water-soluble, polysaccharide hemicellulose that is extracted from the seeds of the tamarind tree (Tamarindus indica), and is not broken down by digestive enzymes. It acts as a film-forming barrier over the intestinal mucosa, helping to reduce the effect of pathogens and to improve the function of the intestinal barrier. It is often combined with gelatin (tannate) to prolong its availability within the intestine.
Gelatin tannate and xyloglucan are promising mucoprotectants forming a protective layer over the intestinal mucosa, which can help restore normal function to a deficient intestinal barrier and reduce mucosal permeability. The studies available to date suggest that these mucoprotectants can be helpful in the treatment of acute diarrhea in both adults and children. As well as improving stool parameters, they have beneficial effects on other symptoms, such as abdominal pain, nausea and vomiting. Importantly, they appear to be safe even in very young children, and thus may provide an alternative to drugs such as loperamide that can be associated with serious adverse events such as lethargy and ileus in young children]
Noventure have several products (Gelsectan, Xilaplus, Tasectan Plus or Duo)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4628347/
Xyloglucan for the treatment of acute diarrhea: results of a randomized, controlled, open-label, parallel group, multicentre, national clinical trial (2015)