(Not a harem, not a system, please enter with caution)
You ask if there are any colleges for cultivating immortals in the 21st century? Yes, we do. Our cultivation of immortals should be orthodox, programmed, and routine-based. It should be able to help more innate spiritual cultivators to make progress, and it should be able to associate with well-known overseas schools.
In order to keep up with the trend of the times, we now call people other than immortal cultivators Mahua. If you ask what they were called before, of course they were called mortals!