I used to have GERD. Fasting and a low carb diet seemed to have resolved it for me.
Supposedly GERD is caused by too-low stomach acid. I used to drink apple cider vinegar with water, and that seemed to help. I am also careful not to drink too much water during or after a meal, or else that seems to lead to some acid reflux and poor digestion.
I wouldn’t take any PPIs until I tried some other things, if I were you. Strong stomach acid is better for digestion, better to fight off food born illness, and helps more with nutrient absorption.