You are not alone, have read many people suffer from low cognitive function while dealing with candida. I know my Cf is limited compared to where it was only a year ago, let alone where it historically was. It is VERY frustrating and more than alarming....
IMHO, I think it has to do with Adrenal Fatigue/Hypothyroid issues. One symptom of AF/HT is lower body temps which dramatically effects cognitive function (you can test this through body temps, if low it suggests AF/HT). These endocrine systems are part of the body's flight/fright response and it one is already in a state of AF/HT when under extreme stress (say perhaps from trying to get well from a complicated disease or, stress from loss of cognitive function) it will only further drain adrenals/thyroid hormones. These systems also regulate so many body systems, body temp, blood sugar, immune response, HCL levels, sex hormones, etc.....a long list...
There are adrenal support, Iodine
supplementation (major nutrient to thyroid function) and other CZ forums which may help give you a better footing on how to proceed forward. Nutrition (NB) is a critical component, no doubt but, my personal take is far too many nutritionists think they are MD's: which of course they are not.
Highly suggest embracing candida as a symptom of something else which requires treatment and will eventually correct candida levels, rather than sticking to trying to deal with candida as a stand alone.
Blessings upon your healing journey.