He might choose a phoenix feather because it represents rebirth and magic. And for the wood, perhaps he'd pick holly, which is often associated with protection in the wizarding world.
Perhaps it was related to some new and untamed magical ability within Harry. For example, if he discovered a hidden power within himself that was too much for his wand to handle. His wand, which was made for normal magical use, couldn't withstand the intensity of this new power, and thus shattered.
He might become more vulnerable. Usually seen as a powerful and cold - hearted villain, losing his lover could expose a softer side. He could start to show emotions like sadness or regret that he has never shown before.
One possible fanfic could be about how Harry discovers new and unexpected powers of his wand. Maybe it starts with him accidentally using the wand in a way he never has before during a simple spell - like making a flower bloom in an extraordinary way that defies normal magic. This could lead to a journey of exploration as he tries to understand the true potential of his wand, perhaps with the help of Hermione and Ron.
Harry might be initially shocked and angry. After all, his wand is an important part of his identity as a wizard. He could lash out at Hermione immediately, demanding an explanation for her actions.
One possible reason could be a moment of sudden realization. Maybe Draco realizes that Harry is in a dire situation where he needs the wand to defend against a common enemy. It could be a sign of a shift in Draco's character, from being an antagonist to having a moment of altruism.
He might choose holly. In the original series, Harry's wand has a holly wood. Since he's making his own in this fanfiction, he could still be drawn to it for its traditional associations with protection and courage.
He might face backlash from his own side. His family or the other Death Eaters, if it's set in that kind of context, could view his act as betrayal. They would likely be angry with him and might try to punish him in some way.
He might have lost his main means of casting spells. This would put him at a great disadvantage in any magical battles or challenges. Without his wand, he would have to rely on other forms of magic or his natural abilities, which could be much more difficult.
Often, the plot of 'Harry breaks his wand fanfic' starts with the accident or incident that breaks the wand. Then, Harry has to face immediate challenges like not being able to perform basic spells for protection or daily tasks. He may then set out on a journey to either repair the wand or find a replacement in an unorthodox way.