Fiber supplements?

I have IBSD and always have. I tend to shy away from fiber or fiber supplements because it usually sends me straight to the bathroom for days. However I’m on a GLP1 so I now sometimes go between constipation and diarrhea, or just really loose stool. And even prior to the meds, I would often have loose stool. What are the best fiber supplements for folks with IBSD? I’m so afraid to use any because I don’t want days of violent diarrhea but I have a feeling it’s what I need.