All the tips, except for those with additional acidity or flavor enhancers - so sauerkraut, citrus fruits or maggi (glutamate!) - are good and help relieve heartburn.
But if you have to fight reflux or stomach acid again and again and fast (!) Remedy, I recommend caustic soda in its most effective way: Bullrichsalz! An old home remedy of our mothers and fathers, not expensive with max. 4.- Euro for 100 tablets plus spare tubes for on the way.
Since not very tasty, preferably with milk or buttermilk ingest, this reinforces the quick remedy. Get well!