I'm not really sure what you're asking, but if you mean have I ever struggled with any particular writing style, I'd have to say no.
Mostly because I don't try to mimic any existing style.
It's been a lot of time, work, and effort, to hone and refine my own style.
If you mean struggling with any specific aspects or areas of a given narrative, or genre, then absolutely the answer would be yes.
We all have our areas of expertise, and the areas that we struggle with, and that's okay.
Personally, I'm not exceptionally skilled when it comes to action/fight sequences, or writing in a Light-Novel stylized, or brevity-driven format.
As for where I'd say my talents are particularly well-honed, I'd have to say it would probably be with the world-building, immersion, and character depth in order to make the world feel real and lived-in. Beyond that, creating and designing game-based systems for incorporation into a narrative.
As for the use of any given PoV, I tend to favor writing narrative in third-person limited, with insight into only the protagonist's thoughts, partially because when I write in first-person, it can be particularly intense, or overwhelming for my readers. As a result, I tend to limit my use of first-person to external preludes/interludes rather than narrative itself.
So, in truth, I can't say that I struggle with writing in either PoV (First or Third), but that has simply come from extensive practice, as well as a lot of reading, and learning how other people have written in the given perspective.