"Finally found a diagnosis causing my foul odor. It's called internal intussusception. My main symptoms were foul odor unrelated to hygiene, incomplete evacuation, constant gas, and the lack of urge to go. Please go see a colo-rectal surgeon an stop wasting your time with GIs. You will need a test called Dynamic MRI of the Pelvic Floor which is difficult to find, you will have to look around."
I think this person was right that we might have something called internal intussusception or Rectal prolapse when the anus becomes loose causing us to release this odor. I believe this might also be what's causing the fecal odor. I found more people stating the same thing, who went to a colo-rectal surgeon, did the MRI test, where diagnosed with the internal intussusception/ rectal prolapse and got cured, you can read them from the websites below.
So when you go to a colorectal surgeon just show him one of the stories or just tell him to check whether you have internal intussusception or a rectocele or rectal prolapse using the dynamic mri test or a traditional defography. If they say yes you have it then you will be able to decide whether to get it fixed through surgery.