I suffered from long covid with mental drop-outs twice last year, plus several "brown-outs". Brain fog was constant. I was sent through a series of cardiovascular tests and even had a heart monitor surgically installed. Brain scans of many types as well. All of these tests showed I was healthy as a horse. Absolutely no issues. I was then set to begin a series of neurological tests but that got interrupted by a diagnosis of mild prostate cancer.

Fast forward, I had a 3 hour prostate surgery under full anesthesia. When I woke up, my brain was perfectly clear and has remained so for the 2 weeks since the surgery.

I understand that long covid could be caused by continued mild inflammation in parts of the brain. It appears that the 3 hours of general anesthesia also resolved any mild inflammation left by covid.

Just as nobody could explain the blackouts or brownouts, nobody can explain why I feel perfectly normal after the 3 hour unrelated surgery.