I don't really feel much investment for Lana, she lacks much of an agenda or agency, or even anything along the lines of personality flaws, leaving very little for a character arc. Her episodes are just kind of random and often don't even involve her own character that much. Even in terms of comedy, she only supplies the odd weak gag, otherwise reduced to background character status with Mallow (whose even WORSE). The other three aren't that well limelighted either but they can at least work with their roles in many episodes and have good chemistry with Ash. All three also have pathos, they may struggle to compete with Ash's clowning and appalling luck, but they are fallible too and at least don't just stand there Joe Besser-ing EVERY time there's slapstick and antic plots. They feel like proper characters you are meant to care about.
She isn't bad mechanics for a character altogether, but she is one for a MAIN character, one we are meant to be invested in. I feel like Lana and Mallow should have been semi-recurrers with Kiawe, Sophocles and Lillie getting more limelight to themselves. They're just not remotely developed or sympathetic enough to be protagonists.