Lots of OTC Remedies to Use- Any Good?

I have been reading on various non-prescription over the counter remedies currently being promoted. For example, Manual, black fermented garlic, and for another, something called Butyrate (uncertain of spelling). Probably others? For IBS.

Any experiences on this site, in this community? Research done?

I have had a long hard winter with almost constant discomfort, pain, and nothing recommended by doctor helps much. Fiber. Miralax. Tried prescription Linzess, caused diarrhea, several days, stopped taking it, doctor knows.

What else?