I highly doubt there would be anything but if there's is I'm in !
https://www.mangago.zone/read-manga/deathco/
https://www.mangago.zone/read-manga/dai_dark/
^She's a deuteragonist but I think it fits
https://www.mangago.zone/read-manga/karasu_ni_hitoe_wa_niawanai/
^Kindaaa fits? She is portrayed by the story as very twisted but she considers herself a good person
https://www.mangago.zone/read-manga/gachi_koi_nenchakujuu_net_haishinsha_no_kanojo_ni_naritakute/
^If you're fine with romance, the FLs in this are pretty insane. The second one ends up regretting her actions though.
Can you recommend stories with a female lead who is unapologetically and inherently evil? I'm looking for characters who don't have tragic backstories or trauma as justification for their actions—just pure, unadulterated malice.