The reason we do a colonoscopy for someone with your type of condition is to check for Tumours, Polyps, Inflammation and also to take biopsy to check for conditions where the colon looks ok but the biopsy gives a clue.
In your case it is not tumour or polyp or inflammation. So the question is did they take biopsy from colon to check for conditions called Microscopic colitis, Eosinophilic colitis etc? If they haven’t, then only Yes.
I am not sure if you had tests/assessment/treatment trial for
Thyroid, Coeliac, Bile salt malabsorption and Pancreatic exocrine deficiency. The thing is these conditions give exactly the same symptoms that you report. The thing that would be unusual with IBS is weigh loss from it.
Hope this helps.
All the best.
J G S R clinic