A quite note on pickled vs fermenting: pickling usually refers to a vinegar solution that preserves but isn't fermented (so it isn't a live culture). Fermenting is usually just water and salt, promoting the lactobacilus in the air and slowing down everything else.
I wish you the best! Gut health is important, and very much still a black art.
I see, good to know about pickled vs fermenting, I learn something new every day.
Another thing we're trying with regards to allergies and other immune issues, is medicinal mushrooms. But that's a whole topic in itself and maybe only tangentially related to gut flora.
It's fascinating the medicinal/curative potential of bacteria, molds and fungi. The posted article mentioned 100 trillion microorganisms in the human microbiome, that's astronomical.
I wish you the best! Gut health is important, and very much still a black art.