AMS is real. I see it in my line of work all the time. The biggest issue with AMS is that there is lack of awareness. It could be easily avoided or minimized but a lot of high altitude adrenaline seekers often get it for one simple reason, ignorance!
One simple rule of thumb is that you don’t ascend more than 300 meters beyond 4000 meters per day when you are climbing high mountains.
You need to give your body enough time to acclimatize.