A theory I like about the next Avatar that I’ve heard is perhaps she has the hardest time with her native element of Earth. She can’t bend it at first no matter how hard for she tries. She’s not stubborn, meek, not very confident in making her own decisions. And going of of an idea you said about her coming from poverty because the Avatars we’ve seen have been royalty or from important world leaders. And perhaps she invents a new bending technique for firebending
I think a more interesting earthbending avatar, if we’re going to make earth the hardest for them, would be someone with an affinity for air. Not meek, but more detached. They don’t have an interest in setting down roots. I’d imagine they’d have a very airbender-mindset. They could be a nomad. Ever hear of an earthbending nomad? Not likely. So low and behold, when she finds out she’s the avatar, it makes no sense to her, because earth would be her base element, but she’s never been able to lift a pebble!