It sounds like your specialist is selling you expensive supplements. You don't need such expensive supplements. BioCeuticals are outrageously expensive.

1000 mcgs of methylcobalamin B-12
1000 mgs or more of D-3
a single B-50 Complex
a magnesium or calcium-mag combo. Not mag oxide. Mag citrate is fine.
any fish oil with decent EPA/DHA

Adding the common anti-oxidants will help (C and E). Oxidative stress is rough on a struggling brain. 1000 mgs of C twice a day is good. Some take twice that. 400 iu of E.

No need for fancy or expensive brands.

It is far more important to get started and stay consistent that hesitate while looking for the best (if there is even such a thing). The issue is more about avoid the junk than finding the best researched and likely overly hyped.

I wonder why your specialist omitted a good B-12 dose ? Maybe he is more focused on selling his products than getting you what you need. The things you took were limited in value without a B-12 and B-50 Complex foundation.

Why do you buy a supplement but delay taking it ?