> But things like autoimmune issues, persistent 15-year brain fog (I'd rather call it frosted glass layer) which randomly clears once a month to remind me how nice it is to be able to think straight

I've been experiencing something similar for the past 5 years: brain fog (frosted glass is a much better way of putting it.) and some short term memory issues. The doctors put me through a battery of tests to find...that they could find no reason for my ailment. Curious to know what if anything has helped you the most. The 'randomly clearing' brain fog for a day happens to me maybe once every 3 months and it's both a blessing and a curse.