I would consider trying out zypan next if the betaine HCL doesn’t work. I never tried betaine HCL so am unsure how effective it is; it sounds like others liked how it works though.
I believe the gas is from fermenting foods in the gut; in time, as you improve your digestion, it should improve or go away.
Are you eating meat right now? Someone on the forum mentioned that when the reduced/eliminated meat consumption, the gas went away…