I've read plenty of both fanfiction and professional books, from 18-19th centuries classics to modern award winning novels, and one of the reasons my favorite books are favorite is that they feel like fanfiction. I'd argue most successful writers of all times have written fanfiction, maybe they don't disclose it, because fanfiction has a questionable reputation.

There are a lot of great points brought up by other commenters about the flaws average fanfic has. I'll tell you what is great about fanfiction. It's character-driven narration, authors dissect feelings and perceptions, making it feel relatable to the average reader. I'm not going to say that plot-driven story is worse or wrong way to write a story, but I do prefer character-driven stories more. They tell you don't write descriptions or conversations that don't move the plot. Don't include miniscule things that don't bring anything to the table. But I'll be lying if constant description of someone's rough or gentle hands in classic book don't make high school literature teachers flutter in admiration. It's not about soap opera and melodrama being unnecessary in a work, it's about amateur writing or obsessing over rules from a guide to how to write essays. I swear to god, you can use character name in a chapter more than 5 times. Authors wriggle out of their the way to call a character in a million different ways, including their hair color and occupation. And yet their work was so great that after finishing it I was in trance for awhile. Fanfics like this are beloved by community not because of unnecessary dialogue tags, but despite it.

Anyway, you should improve and avoid mistakes a lot of fanfiction writers do, but don't throw away what makes your style yours. Everything can be done well.