Hello smithy1928,
Welcome to the NeuroTalk Support Groups.

My daughter had extremely low B12 and it affected her cognitive abilities. She was in her early 20s when it was finally picked up. She'd had years of struggling to study and to think clearly. A regular doctor/general practitioner here can organize B12 testing.

I wasn't aware that magnesium could make akathisia worse

It is definitely work investigating in my opinion.

take care