Make nitro used themes available when nitro ends

Basically what I mean is, say I find a theme and use it with nitro, then my nitro ends and it goes back to the default. Instead why not allow me to use the themes I had used when I had nitro ? In this case Crimson Moon, Midnight Blurple, and Forest are all great themes and I really like them and would love to still use them even without nitro, since I used them WITH nitro shouldnt they still be available to me after my nitro ends ? AKA I basically “Unlocked them” so to speak