Not sure if some of you fine folks understand the difference between a video game and a live session with an actual DM.
You won't be able to send a chat message to the Larian developers, come up with a personal background and have them patch it into the game.
These background options are tools that you and your DM work through to tie you into the game world in a way that is not feasible with a video game.
The more generic you make them the more meaningless they are to reference in the game.
They still have in game consequences of giving you abilities you otherwise wouldn't have access to.
Larian has chosen to focus on reacting to your in game actions instead of some nebulous and generic tag to determine how the game is going to react to you.
IMHO that is a much better option as it makes what you do in game more meaningful with consequences as opposed to the game reacting to a checkbox during character creation.