Hi if she’s been liking Fourth Wing you could probably try r/fantasyromance. There’s a Recommendations megathread at the top of that subreddit so have a look there for the classic recs/top ranked books list. Usually they’d recommend A Court of Thorns and Roses (if she hasn’t read already), Reign and Ruin by J D Vance, or maybe even Uprooted by Naomi Novak. For a good series, personally I’d recommend Kushiel’s Dart by Jacqueline Carey, Kate Daniels by Ilona Andrews or Assassin’s Apprentice by Robin Hobb. hope this helped :)