I think people are misunderstanding Luffy's Fruit and how it's still very much proof of hard work
The Nika Fruit gives freedom to the user and what it can do is based on said users imagination, as well as being limited by that imagination. Most people who receive this fruit would probably immediately think that being made of Rubber is a lame ability and that there's no useful way to use it, and therefore would never bring out even a fraction of the fruits potential. We see this constantly as people say being made of rubber is a useless power, yet Luffy says Rubber is very useful and has a lot of potential. This is probably why no one has awakened the Nika Fruit in 800 Years, no user outside of Luffy has been so creative and imaginative with the fruit since Joyboy of the past.
So no, I don't think Luffy having a Mythical Zoan negates the hard work he put in to get here, we all know he hasn't been carried by his Devil Fruit. I mean ever since the Timeskip, the emphasis has been moreso about his Haki and developing that, which also took lots of hardwork to develop, so him finally awakening his Devil Fruit and having it be special doesn't negate every trial and tribulation he's been through