Brain fog is really terrible, I've had it permanently for years accompanying chronic fatigue without it letting up for even a second. It's like one day the switch for my cognitive capabilities just flipped off and it was permanent for me. Did this happen to you, or do you only have it in bursts with moments where it alleviates itself somewhat? (Like in moments where you have slightly more energy, your mood is better, or you ate certain foods that day?)
There's a lot of different things that can cause brain fog, it's such a nebulous symptom resulting from a variety of disease sequelae. For example, vitamin deficiencies, inflammatory/autoimmune conditions, diabetes, sleeping disorders, mood disorders, miscellaneous neurological conditions, the whole gamut.
If you haven't already, it's probably a good idea to get a cursory blood test and see if you have something like a vitamin deficiency or inflammation, because some people's brainfog actually does improve if they treat the underlying issue in a timely manner. While I can't find any great studies off the top of my head on it, a lot of people who have taken psych drugs (myself included) end up with some kind of vitamin deficiencies from long term extensive prescription drug use and aren't monitored for it.
I've spent years and loads of money trying to fix mine, with no dice. However, I have a structural abnormality of the brain that is salient enough to show up on an MRI, though I'm not 100% sure if it's the cause of my cognitive issues with learning, memory, eyesight, focus, attention, etc. So while a lot of things didn't help me, I think it is certainly possible for certain people to experience some semblance of alleviation if the actual cause is pinned down and identified. The hard part is actually taking a stab at figuring it out how/why it happened on a cellular level.
Your job sounds like it would be really challenging to do while struggling with these symptoms, there's a misconception that "low skill" work is easy but I've always found things like food service to actually be really difficult and requiring a lot of attention to detail and ability to work extremely quickly. That sort of breakneck environment is hell on earth if you're having focus and memory problems.
I hope you can get out of that job at some point, having a workplace that doesn't mesh well with your disabilities/health conditions can be soul crushing and I know it has to be so hard for you going to that day in and day out knowing you're gonna struggle. Wishing you some relief.
