Intermittent fecal/sulfur breath odor

After scouring the web, I'm certain I'm not the only person with this problem, and not the only person who's been told they were imagining it. Anyway, the issue is I have intermittent odors when I talk (yes, I've been to the dentist 10+ times-- all say my oral hygiene is on point and xrays and inspections showed nothing). The only time it's practically non-existent is when I eat an unhealthily low-carb diet. Like others online, I've had CT scans, Barium swallows, endosocopy/colonoscopy, screening for parasites (getting one more from an IDS before crossing that off my list). All showed up negative. I tested positive for SIBO, but after researching that for the past 3 years, I'm certain SIBO is more of a symptom than a primary causal problem. Furthermore, even when I treated SIBO with heavy antibiotics, it did absolutely nothing for my breath-- and yes I was cleared of SIBO after a couple rounds of work. yet, the moment I eat carbs, I still get a "did someone just s*it themselves?" comment.

I guess what I'm getting at is I'm tired of doctors just saying it's IBS and SIBO and then proceeding to do zero investigating afterwards. I want to get down to the root cause of this, but most doctors are either too apathetic or too incompetent to do anything. Are there any researchers who specialize in studying and diagnosing hard to find problems in the GI tract? Between the 3 GI docs, 2 ENTs, 2 NDs and 1 IDS, I just can't take normal doctors anymore. I want my life back and I want a specific root cause so I can work on progressing from there.

Further notes: Diarrhea actually cleared up when I ate junk food and I had zero bloating, albeit the odor remained.

Xifaxan and neomycin did nothing for the odor, nor did the elemental diet. I actually think the elemental diet made the smell as bad or
worse than before.

*******Nitazoxanide********** worked wonders for the month I was on it. Solid stools even with foods that normally cause my ibs to flare up.
It's exactly the reason I felt there was more going on to everything than just SIBO and IBS.