
they’re both competent and have different motivations but I’d argue that Aria is more competent. Mia’s main goal is to prevent her future death and while she has successfully done that it’s mostly because of the people around her. Aria’s main goal, however, is to ruin the life of her step sister, Miellé. Although right now what she’s done so far may seem like just petty remarks, it shows that she’s slowly eating away at Mielle causing her to act more recklessly and almost expose herself (carriage incident). Aria is slowly getting people to change their opinion of her too. I also like how instead of becoming instantly kind like what happened to Mia, Aria is portrayed as a bad person instead of making her do a 180 on her personality.
I believe Mia is much more competent than Aria from The Villainess Reverses the Hourglass!
They have similarities with each other but one of the differences is that Mia has always a way to get back at her opponents and her motivation + capabilities are not underminded by any MLs.