Adding preload doesn't change the fork's resistance to bottoming out, it just makes the fork feel stiffer when you initially push down on it. Much better off just getting the correct spring for the fork to be honest, which is why most forks don't come with any preload adjusters.
Most forks did come with a preload adjuster (we are in retro, no idea of modern). It allows you to adjust the usable
travel for the given range of the spring. Only the budget forks didn't or didn't make it as easy.
also given a spring would never be fully compressed, it alters you start and end stiffness (at the end of the stroke the spring would be compressed by that initial preload reduction also.).