There's various hints throughout that mean she might be involved with the next new hero. She mentions that she built drones to help around the house and help her folks. This means she might be some kind of summoner.
Later she mentions she wants to build a robot that can help keep us safe. So she could be a summoner and they can potentially be omnics that follow teammates and heal them. They might shield them, they could boost or buff them like Mercy's staff, etc. Things of that sort.
She was asked what she was going to do with her grant money and she said,"Oh! I have an idea." Which means she's going to build a robot.
Obviously this all speculation but the concept of a support summoner hero is magical. But because she's a character that is only 11 years of age means that she wouldn't be a playable character. If its not Efi herself that's the new hero it could be a giant robot omnic that's the actual next hero.
This is exciting news! And she's African, how very diverse!
*sings* Do you wanna build a robot?