DGL has healing and anti inflammatory effects on the throat and stomach lining. If you are on PPIs because of ulcers, gastritis, or other stomach lining irritations then DGL will definitely help that. It won't prevent or stop heartburn, and it won't help you wean off PPIs, but if you have stomach lining irritation, then it's certainly an appropriate remedy.
If you have high blood pressure, you might want to check with your doctor first. The glycyrrhizin in licorice root can cause issues with hypertension. It has been removed from DGL, but there is no standard for the % left in any given brand of it, so check the label to make sure it's less than 2% glycyrrhizin. If the label doesn't specify a glycyrrhizin level, monitor your blood pressure daily for a couple of weeks after starting it to make sure it's not having an adverse effect. Then monitor weekly after that, if taking it long term.