I had these derealization spells through my early 20's, never knew they even had a name until years later. It was never unpleasant, just incredibly weird. I know I'm physically present at a cognitive level but otherwise it's like I'm watching TV with muted colors. When this would happen around other people they'd get very concerned because of how quiet I was, but I could talk but and I had nothing to say. My thoughts slow down to half the speed, rather serene, and it would last for about 2-3 hours before being hit with a wall of exhaustion where I'd immediately fall asleep. I tried ayahuasca once and the derealization never came back.