No one wants to read a novel where half of the characters could be replaced with cardboard cutouts and have no effect on the story, yet so many authors struggle with that very thing; even professional ones. We all know the criticisms of wooden and flat characters who never develop, but what to do about it is not so obvious.
I can tell you though, the answer is probably not found by playing 20 questions with character sheets. You’re writing a person, not a profile.
Me? I turn to nonfiction.
One of my favorite books is Chakras and Their Archetypes by Ambika Wauters, which I highly recommend. It gives a good breakdown of dysfunctional personality types, then contrasts it against what the strong, functional personality looks like. While a person may be weak in one area, they are likely going to be strong in another.
I think that something writers forget is to make their characters internally balanced in some way. Joe may be a maniac bent on power, but he fixes up injured birds in his backyard. Throw in some exposition about the bird bath owned by Mrs. Roberts, who always fed him cookies after his dad beat him up, and the characterization practically writes itself. Why is he bent on power? He hated being helpless and hurt, and thinks that it will protect him. Why does he help injured birds? Because he secretly relates to them, and thinks about the good that Mrs. Roberts had in his life, even if it was just a tiny part. Joe isn’t bad, he’s just badly damaged. Maybe he’ll find redemption, maybe not.
Hey, that wasn’t hard at all.
Archetypes are useful tools. Personally, I think they are a little too one-dimensional to base a character entirely off of one archetype, but combine a few in different areas (a rebel with people, but a caregiver to animals), and you can build some unique and dynamic characters.