Hi! have you read these? Not sure if they’re the one you’re looking for but they’re still worth the read
https://www.mangago.me/read-manga/hwang_young_s_misery/
https://www.mangago.me/read-manga/a_room_without_space_side_story_1/
https://www.mangago.me/read-manga/absolutely_ruined_love/
Omh sorry I clicked on the wrong comment
I found these in my list under "butler", "servant" and similar context
no drills but butler MMC:
Akuyaku Reijou no Shitsuji-sama Hametsu
It seems My Lady is the Villainess with Only a Bad End, so I'm Thinking of Saving Her
I Raised an Obsessive Servant / My Ray of Hope
no drills but butler supporting Ch / ML:
The Daughter of the Albert House Wishes for Ruin
The Result of Being Reincarnated is Having a Master-Servant Relationship with the Yandere Love Interest
When I Woke Up, Twenty Years Passed!
is it this one? her ends is curly drill-like so i think it counts
https://www.mangago.me/read-manga/the_daughter_of_the_albert_house_wishes_for_ruin
thanks guys! it was the albert house one
it was a villainess manga where the mc had curly drill-like hair and she was close with her butler, who i think was the same age as her? takes place in an academy setting and she tries to act like a proper villainess but just ends up unintentionally being nice to the OG heroine.