Writing a published book compared to fan fiction.

I've been reading fanfiction for over a decade now and I've. Just recently started writing my own fanfictin to gain confidence in my own writing as I would love to publish my own body of work some day. Recently i have seen a lot of people talk about fanfiction is always better than published work. Which for the most part I agree. I feel like the plot lines are just more engaging. My question is how do I not fall into the same short comings of other published works. My other question is smut is there a different writing style between fanfics and published works when it comes to sex scenes. I know that for fanfiicton most things go; but can you just as explicit with published stories? Idk I would love to know what you guys think.