Hi, Donavon.
When was the last time your upper GI tract (including stomach) was scoped? If you do have strictures in the small intestine, or other upper GI tract issue(s), self-diagnosis will only get you so far without the help of a medical professional. You obviously know this, as you are trying to get answers through them.
I've been on the 'Net and have seen "this, that and the other thing" re: excessive gas/belching from the stomach. You may have already seen this from Cedars-Sinai:
https://www.cedars-sinai.org/health-library/diseases-and-conditions/g/gas-in-the-digestive-tract.html
Johns Hopkins has an investigative GI group of physicians who tackle "mystery" GI issues, also.
You sound quite frustrated with the lack of solid diagnoses and/or science-based resolutions for your issue. If I were experiencing your excessive gas/belching, I would look for another GI group, with list of concerns, questions in hand. I certainly would not press forward with any medical procedure proffered by a medical specialist along with a shrug of their shoulders. ("Maybe it will work? *shrug* We're not certain...")
All things considered, the CT with contrast may be a reasonable next step with another blockage. Until then, perhaps starting a detailed food diary could be helpful: without being able to eat vegetables and fiber, perhaps too many carbs, lactose intolerance, etc. could be a contributing factor in the excessive gas production.
I'm no medical professional - nor do I play one on TV - but I will say this: Donavon, you're concerned enough about this situation to continue looking for answers. Don't stop until you're satisfied! Continue to be your own advocate and research what you can, talk to everyone who may have an insight. Someone has an answer and/or solution for you...it's just a matter of figuring it out who it is.
Please keep us updated, Donavon.
Lily17