When I first got over my extreme constipation it was because of Betaine HCL and digestive enzymes, i don't know which one caused the change. I burnt myself out at a point years later and those two stopped working, it took a lot of experimentation but I found DGL, a form of licorice, gave me regularity so i chewed 2-4 of those a day and eventually I stopped having to to be regular.
Lately I've been taking nutrients in powdered forms and seeing great benefit. Whey protein powder, pea protein powder, even some ration tabs that turn to powder when chewed, they all give me energy like nothing else has. I'm guessing the reason these work is because my gut is really messed up and these powders are easy for the body to take in. Maybe such powders would help you too; proteins making you more hungry seems like a stomach acid thing since the acid is needed to break the proteins down but considering your taking HCL i don't know anything but the powders to recommend for the hunger. Maybe you have some Small Intestinal Bacterial Overgrowth, you did say you did a hydrogen test right, is that the kind that would have picked up dysbiosis?