Nothing profound here, just a thought.
I wanted to mention something quick about betaine. This is not related to the HCl portion, but just the betaine. Tri-methyl-glycine (betaine) is a very strong methyl donor and taking many betaine caps could result in over-methylation especially within the context of low other b vitamins. B1, B2, B3, B6, pantothenate, and biotin, and whatever else.
It may be worthwhile experimenting going off betaine HCl and trying some apple cider vinegar caps (ACV), instead.
ACV is not as acidic as betaine HCl, but it has a decent amount of acid, and many people do well with it. But it also doesn’t have so much methylation potential! So I figured it worth an experiment.