I am frankly flabbergasted that we haven't had a proper "World of Barbie" game.
Like, one that pulls all the different incarnations of Barbie together.
Start out as uhh... Mass Effect Barbie (sorry, Star Light Adventure Barbie) going around the universe, then on each planet, you get to add a location-appropriate "skin" version or canon other character that'll help you in your further adventures.
Water planet? You're Mermaid Barbie now.
Oh you need to get into the palace, and the princess looks like you? Time for a Princess Adventure Barbie!
etc, etc.
Yes, I know it'd be asset heavy, but... you definitely don't need to do super-AAA megatexture bullshit or 50 billion tris per model, because it's Barbie.
Lean into the plastic and toy look, like the LEGO Builder's Journey game.