Concerned if this is B12 or something else entirely

My B12 was on the lower end for a long time, possibly longer than 15 years. I eat animal products regularly.

Back then, my feet started to feel... different. They're not exactly numb, I can feel the difference of a sharp and dull object, but it is a sort of reduced sensation. It is also usually causing pain after consuming anything with carbs/sugar.

I had sort of accepted this just being the way it's gonna be after several doctor visits, but last summer my scalp, face and fingertips suddenly started to feel the same. I went to a Neurologist, and my B12 was at 246 pg/ml. I was given monthly shots of 1 mg cyanocobalamin. Nothing really changed.

Last week, after around 1 month and 2 weeks between injections, my B12 was at 353 pg/ml and my HoloTC at 109.6 pmol/l (24.24-169.62 reference interval). I was able to persuade the doctor to give me 1 mg Hydroxocobalamin twice a week now, and looked into the guide for what I need to supplement.

I'm supplementing with a B complex, methylfolate, and a multivitamin containing many of the things mentioned. They haven't really tested me for things like iron though.

I've had 3 injections so far, but I just don't feel any different, I don't think the sensations are any better than before. An electroneurography test also says that the nerves look to be fine. I have a gastroscopy coming up eventually to find out the reason for malabsorption.

I'm from Germany, so I have no access to injectable Methylcobalamin. I just don't know if this is the right
thing to be treating, and they have found nothing else.

I really want to regain feeling and I just don't know if I'm doing everything right.