1. First you write that there is some "true" beauty, but then you write how people have different preferences. Which one is it?
2. What benefits does an undercover "true beauty" (whatever that means) get? In your owns words, a girl who puts in the effort is going to be better off when it comes to attracting men than a girl who hides everything underneath baggy clothes and plain face.
3. Why would women keep themselves attractive at all? Basic reproductive success is guaranteed for women, so why bother? In other animals, females are rather dull compared to males. Examples: peafowls, sage grouse, lions etc.