geezer7491,
There is not a proven valid test for food sensitivities. You have to do the hard work with an elimination diet. A food allergy is different from a food sensitivity. As we age our ability to digest things like dairy and beans decreases. Stress can exacerbate digestive issues as adrenaline messes with digestion. Total carbohydrate load per meal is a trigger for me.

Recently I started taking 308Tera a prebiotic developed by gastroenterologist Dr. Will Bulsiewicz. I started out at 1/8 tsp once per day, then 2x/day. I am now up to 1/4 tsp/ 2x/day and will eventually work my way up to the 1 tsp/2x/day that is recommended. I had minuscule bloat with the first 1/8 tsp dose and after that have had no side effects. It is amazing how it has improved my stools. Looking forward to seeing how future doses help my digestion. I know it helps with butyrate production which I need as I am missing my cecum where the majority of butyrate production occurs. Butyrates help tamper down inflammation. If you care to check it out here is the link: https://38tera.com/pages/science
Another thought is for you to look into Dr Norm Robillard's fast tract diet, which emphasizes eating a diet low in fermentable potential (FP). He is a microbiologist who had acid reflux for years and found when he reduced his fermentable carb load it went away. His app gives you portion sizes for various foods. I check the fast tract app against the FODMAP app to determine the fermentable carb load. Sometimes a food which is FODMAP safe is too high in fermentable carbs on the Fast tract diet app.
The Fast Tract diet has helped many people with SIBO and acid reflux. https://www.fasttractdiet.com
If I have a SIBO relapse I lower my fermentable carb load for a few days and it goes away. I never let it get out of control, at the first sign of bloat or acid reflux I curb my fermentable carb load.
Hope this helps a little:)