Long term visible abdominal distension, not gas. Anyone similar?

Hey, i'm a young woman and have had constant, visible, forward-protruding abdominal distension for 2 years. I'm desperate for anyone who has experienced something similar or has any ideas.

The key features:

• Distension is present from the moment I wake up (depends on how much i ate the day before), and worsens progressively with every meal throughout the day
• No specific food triggers: it happens with every food type, including plain rice for 5 consecutive days (but the distention correlates with the food volume i eat)
• Improves significantly only with prolonged fasting (2-3 days) or severe undereating
• Strong diarrhea during menstruation instantly resolved the distension temporarily on those days (until I ate again)
• At-home stool transit test: First test: color appeared after 17 hours, then reappeared over the next 2-3 days ; Second test: color appeared after 48 hours, then passed again in separate episodes over several days

What's been ruled out:

• SIBO breath test: negative
• Celiac disease: negative
• Blood work: all normal (CRP <0.3, ESR normal, full panel)
• Abdominal ultrasound (at the gastroenterologist and gynecologist): normal (A physical exam noted mild bundling/adhesion in the right ileocecal region)
• Abdominal X-ray: notably showed gas-poor bowels despite visible distension - so this is NOT gas

What hasn't worked**:** Simethicone/espumisan/, digestive enzymes, probiotics, activated charcoal, Iberogast, oregano oil capsules, ginger capsules , Macrogol/dulcosoft/, Bisacodyl/dulcolax/ (causes diarrhea but no effect on distension), Prucalopride 28 day trial (regular stools, zero effect on distension), Mirtazapine 15mg (23 days, no effect) + every elimination diet including lactose-free, low-fermentation, and plain rice.

The paradox I can't figure out**:** Distension appears within 1-2 hours of eating, too fast for physical content to accumulate. But it takes at least 1-2 days of fasting to resolve. This doesn't seem to fit a simple motility or gas explanation.

Has anyone had something similar? Any diagnoses, tests, or treatments I haven't considered?