I, too, have had diverticulitis, treated with antibiotics.
To your point of using antibiotics for a flare-up, I had severe cliff 3 years ago. My pcp consulted with an infectious disease doctor about future use of antibiotics, her recommendation was when needing antibiotics, use along with vancomycin to hopefully prevent another bout of cliff. Since vanco seems to be the gold standard for cliff. The way it is prescribed for me is as a way to prevent it.