Harry has never had a huge role in the show... he's been focussed on in a couple of episodes, but he's generally a background character. I think Floss could be a strong character, but in a quiet way. I do think she'll be developed in time, but they're playing the long game with her.
The most focus Harry had is when he had his own central episode in the last series of TBR. If the show continues then he might have more episodes focused on him as he gets older.