I think a writer being a fan of a property can actually hurt their work, if they indulge their fannishness too much -- as we've seen with things like Steven Moffat's Doctor Who and Terry Matalas's Picard. It becomes more about geeking out over how cool the characters are and wallowing in nostalgia rather than just telling solid stories.
Picard season 3 reminded me a great deal of modern comic book storytelling, where a creator wants to tell a story -- or, sometimes,
retell a story -- with the characters and situations as they were when he was a kid, oftentimes tossing inconvenient things away (sometimes in extremely hamfisted ways--cf.,
One More Day) to get there instead of building on the past. It seemed to me that Matalas's vision was to do his own version of "Best of Both Worlds," and I know that much of fandom creamed itself at the recreation of the bridge of the D, but the promo shot of the bridge, with everyone in their places, looking older (as we all are), struck me as a complete failure of imagination and a waste of potential. Like, his idea of a "grand finale" was just to go back to where it all began and play with the toys he remembered as a kid. (See also: Geoff Johns' love for Barry Allen and Hal Jordan, shoving aside their far more interesting successors to get there.)
Of course, my platonic ideal of
Picard was three seasons of Jean-Luc Picard as a vintner, competing against a rival (ideally, Ian McKellen) in interstellar wine competitions, dealing with the business of a winery, and fending off grumpy customers. Very 1980s BBC. So I might not be the best judge.