Of course MC will give more attention to the "little girl" instead of the others, "little girl" is easily the best girl of the story:
She was the only person to extend a hand to MC when he was at his lowest point in life and probably dealing with depression thanks to his s**tty previous life, nowadays it's easier for a bunch of chicks to gather around him because he's getting stronger and richer, but when he was a nobody doomed to be a trash even in this dungeon world (before discovering the seed dungeon), only the "little girl" was there to help, support and comfort him despite she being homeless and very poor and them both being complete strangers to each other.
So yeah, he should always treasure "little girl" above the other girls because "little girl" is the best girl and a keeper.