See if you have GAS... Chronic gas, either burping or the tooting, increases pressure in the GI tract and pushes stomach contents UP creating reflux.

Beano can help with gaseous veggies, and lactase enzyme for dairy intolerance.

Some people with low acid naturally (achlorhydria)...which can occur in up to a third of older patients, do well when using Betaine HCL supplements. This increases acid, and helps digest protein. Undigested protein ferments in the bowel by the bacteria there and creates alot of GAS.

Gall bladder issues, create gas also. Gluten intolerance.
And for me, fructose was a culprit. A huge problem for me.
If you cannot eat alot of fruit or drink apple juice that would he a big hint for this problem, which often goes unrecognized by doctors and patients alike.

Coffee and chocolate also can make reflux worse. And reflux in a diabetic may signal a neuropathy of the stomach called
gastroparesis.

DGL licorice is very helpful for some stomach problems. It can actually heal ulcers in some people. Make sure you use the DGL type, which does not affect the adrenal glands or blood pressure negatively.

I think diet is a big cause of reflux. I had it terribly when I was in my 40's. I have a huge serious hiatal hernia from my GI congenital defect..malrotation. I only needed meds for 3 mons and started the EFAs back then, and it all healed up.
You might add Flax oil to your fish oil... I think flax oil helps alot too.