unironically, this has become my favorite approach to character background over the years. Build out what the character can do, first, maybe pick a theme too. But create the character you want to play when you're at the table. The first few encounters are a great forge to make a character from, and then you can extrapolate and improvise from there when necessary.
Can't have conflicting backstories if you don't write a backstory. My latest character was Gruk the Orc. His backstory was one word, smash.
save