TBH, it felt like JKR was “burned out” to some degree when she wrote HBP. I mean, at the start of OotP, Harry’s not handling the death of Cedric very well. But at the start of HBP, it was more “meh...bad shit happens, so what?”
Guess that’s the beauty of what started speculative is now AU… I’ve got my own narrative where I can totally ignore HBP and go with a much more twisted narrative. Ask my Ron what happened after he turned his hair black for a night… guess