fivetoedsloth
Been there, done that.
It's called phlebotomy IIRC, and the doc took 1/2 litre each time, which was too much as I began to experience periods of terrifying breathlessness.
So he stopped the blod draws, and left the blood iron at ~1/2 scale, telling me to check on it.
It stayed that way for years, never checked it after 5 years.
My guess is that it was so high because my body was making incompetent red blood cells due to too much zinc (30 mg/day) and vit. C (2 grams)for too many years, this washes out the copper which is essential for making red blood cells. Lots of poorly made cells did carry enough oxygen to keep me alive (unless I'm imagining this life. Must have a sick imagination.)
But very sick for years, until I discovered raw zero carb diet.