Is anyone else’s IBS seemingly unaffected by their diet?

I was formally diagnosed with IBS last year after process of elimination for other issues through a colonoscopy. My only concern is that to me, most studies online suggest IBS is largely triggered by diet, when actually I don’t really experience that very much! I seem to get an upset stomach when i eat out vs at home, but it’s never to the point that I can pinpoint what is actually causing my stomach issues. The typical foods that seem to upset peoples stomachs don’t seem to upset mine (ie high fodmap)

Is this still IBS? Has anyone else experienced something similar and it wasn’t ibs? I am seriously wondering if mine is endo, as my symptoms are the worst on my period.

Thanks all!