Is it their personalities you don’t care for, or do you find their roles in the story uninteresting? Or both?
I can see where Aqua might come off as less interesting than the other major characters since she’s actually pretty normal in comparison. You have characters like Terra/Riku who struggle with self-doubt and being manipulated by darkness, Ven/Kairi who lack any darkness in their hearts, one by natural and the other by unnatural means, Roxas/Xion/Namine who are all mysterious and unusual Nobodies, and Axel who was introduced as a scheming and quirky assassin. Obviously, Sora’s more “normal” than Aqua, but he’s also the Not Special But Still Special Chosen One series protagonist. Aqua’s essentially “just” a duty-bound Keyblade Master who worries about her friends, and there’s absolutely nothing wrong with that, but her role is far-removed from being considered unusual within the lore, and I know some people often prefer mysterious and/or “dark” characters over the morally upright and dutiful ones (on the contrary, I love the morally upright and dutiful ones. lol).
But despite lacking any eccentricities or mysterious qualities, I personally think Aqua’s plenty interesting just by her personality, interactions with other characters, and story themes.
Considering her story in BBS is about her chasing after her friends, she’s set in more of a supportive role, but it fits with her newly given responsibilities as a Keyblade Master. It’s kinda subtle, but she learns to become a better leader; she realizes she should give Ven more space and becomes less protective, and she learns to be more flexible about situations.
She worries a lot about her friends, and I know some people are skeptical of her for doubting Terra so much, but I think she made the Wayfinders in the first place to help appease her own doubts about their uncertain futures together, considering the Mark of Mastery Exam was about to be held, so her worries were exasperated by Terra’s affinity for darkness (and his failing the exam), Eraqus worrying about him, Maleficent lying about him helping her, etc. Suffice to say, I think Aqua worries a lot, but keeps it on the inside. She suffers through a situation where she earnestly believes in her friends and their connection, but she also thinks too much and lets her worries get the better of her. I think at the center of her story is her desire to preserve her bond with her friends, but it’s also about her learning to believe.
Even all that aside, I just find Aqua to be really sweet and a good person. She can come off as stoic and all business, but she’s actually a girly-girl who likes flowers and kids and believes in the power of true love and will sass villains.
I mean no shots at the other female characters or how they’re handled when I say I think Aqua is the most deep and well-rounded of them. I think all of the main characters are deep, but some of them aren’t given quite enough screen time to take advantage of, or they take a little more work to understand. Even just counting BBS, Aqua gets a lot of time on screen due to having her own story, along with the (greatly overlooked, imo) detail that each BBS protag has their own arc in each Disney world that usually relates in some way to their current plot and their overall character development, even if it’s small or takes reading into to see.
I usually learn to like a character better by reviewing.their scenes and trying to understand their motivations, why they acted a certain way or what a line meant, etc. Noticing Aqua’s solemn expression in the background after she white lies to Ven that he’s always lived with them in the Land of Departure, or considering how she patiently and silently waits for Terra’s explanation in the Keyblade Graveyard, without accusing or questioning him first, are cool details that help deepen her character.
Long story short, I just really like Aqua and her interactions with other characters. I think she has a lot of good depth, and she doesn’t need fancy lore to be interesting. I can’t say anything about Jill because I haven’t played FF16, so… yeah. lol
But if you find you’re just not interested in certain characters, that’s totally okay. They may grow on you with more time, or maybe not. Try to avoid forcing yourself to like anyone, it won’t end well.