GERD is often caused by low stomach acid (contrary to popular belief that the cause is high stomach acid) and a defective or loose lower esophageal sphincter. Antacid medications relieve symptoms temporarily but often make the problem much worse.
To relieve symptoms of bloating and constipation naturally caused by GERD you could try adding a teaspoon of apple cider vinegar (ACV) to 4 oz of water at each meal. If you are taking any PPIs you may want to slowly reduce the use over time before beginning ACV.
GERD is also an indicator that there may be additional gut issues present. Avoiding foods that could perpetuate gut issues for a time such as processed foods, citrus, tomatoes, large meals, coffee and alcohol while working to repair your gut issues could help resolve the issue long term.
Some teas that could also soothe symptoms are CCF (cumin, coriander, fennel tea), peppermint, and ginger.