Been a while since I updated, mainly because I've had over a month now to find any connection between my sex-life and my brain fog and I can't find any. I've had brain fog while refraining from sex/masturbation and I've had no issues after multiple days of multiple orgasms, so it seems POIS ... "this is not it" for me/
As it stands, I might have overlooked the (now) most obvious cause all along. I've always been a heavy soda user and switched to Coke Zero exclusively many years ago (not sure when exactly but definitely way before my issues started), like at least 5 cans a day an usually more like 10 cans a day (330 ML/can). I just ran into a bunch of research relating Aspartame and other artificial sweeteners or rather the effects (of reducing/stopping it) as a potential cause for brain fog. It might just be that my body/brain has become so used to the large amounts of Aspartame that dipping below the usual intake triggers my brain fog.
I had tested reducing my soda intake somewhere along the lines but if "not having enough" is actually causing the issues, I probably drew the wrong conclusion. Also, seeing the amounts I use, it could take 2-4 weeks to let my body/brain adjust to withdrawal and I surely didn't test it that long.
I'll be sure to update in a month, I'll be ditching all soda as of today. In the mean-time all the best to all of you in your search to finding a solution to your issues, whatever the cause(s) may be!