One way to pad out your word count and advance character development (not to mention backstory) is to have them either literally have, or imagine having, a conversation with their younger self.

Have they, for example, lived the things they dreamed of having or doing in their younger days?

Perhaps they have compromised so much that they are no longer the person they wanted to be. Do they have excuses they give for those compromises? Do those excuses hold up to scrutiny?

Are there parts of their lives that they should re-evaluate even if they are not consciously aware of the need?

men in black jacket standing by the window
Photo by cottonbro on