Looking for a very specific fantasy book

Hi y'all, I am looking for a very specific book rec.

I need a fantasy with a female lead who gives off the same vibes off Gwaine from BBC's Merlin. I am happy if there is some romance in the book – but it shouldn't be the main focus.

Also, I've read way too many ya fantasies recently, I am sort of over them, looking the character to be in their twenties or thirties.

Thanks!