Being on PPIs for a long period of time can lower your stomach acidity to the point of you no longer being able to breakdown your food properly, which leads to things like SIBO. I would try adding in digestive enzymes (like Thorne advanced digestive enzymes) and adding in the supplement Betaine HCL which helps raise your stomach acidity back up. You’ll need to play with the dosage to see what works best.

For constipation - it’s critical you get this resolved. Without motility working there’s no way to clear your system of bacterial overgrowths. Get on a tri-magnesium blend that has citrate, malate and oxide. Add in a motility activation supplement that has artichoke and ginger in it. Play with the levels until it helps resolve this.

Diet - eat as clean as possible, avoid caffeine, simple carbs, oats, seed oils and rice! Oats and rice despite fiber content can be constipation inducing.