Cider vinegar gags me and I burp or bloat. Yuk
You’re clearly showing low acid which is why you can’t break down acidic foods. No acid and the PPI’s won’t be doing you any favors.
Have you heard of HCL? It is used for people with low acid allowing you to break down foods. If you don’t like that idea a digestive enzyme would also help. I favor Enzymedica enzymes. Very pure.
https://enzymedica.com/
I have also used source naturals with good luck.
The symptoms of both low and high acid are the same. The fact your not breaking down acidic foods also shows you’re low acid.
I studied/ researched nutrition forever it seems to help my daughter as well as myself. Sometimes we can’t FIX these things but we can MANAGE them either with diet or supplements. I would recommend a digestive enzyme for you. Broad based to inclugpce all protein( protease); fats ( lipase) and all sugars and starches ( amylase being the main one )
It could also be something you’re eating like grains? Saturated fats? Sugars? Dairy. All highly suspect foods.