I think the translation is not giving much hint, plus how a webtoon can't show everything going on, I'm reading the novel and I realize there's things being left out compared to it (and some additional things too).
Is not that Ariadne is regretting revenge or that revenge is bad, this revenge feels wrong for her precisely due to how anticlimactic is, Lucrecia kept her lips tight regarding Ippolito's father, and Ariadne feels is unfair that a shit like Ippolito is the receipt of unconditional maternal love when Ariadne herself is alone, her own mother has passed away and Arabelle died alone on a bed.
And yes, is frustrating.
not a fan of the 'getting revenge is sooo bad cuz you won't be happy in the end uwu :'(' trope. you can really feel the preachy catholic undertone sometimes.