How many of these are there? There seem to be a lot where a villainess time tavels and becomes a nice person, or where a real person isekais into a villainess and becomes a nice person, but not many where a nice person becomes the villainess or a real person isekais into a villainess and actually becomes a villainess.
There are at least 4 that I know of.
One of them is hardcore depressing one. The MC can't even be considered a villainess, but she still views herself as such. Reading it is like walking barefoot on glass.
Then there's a "villainess" that looped for a 7th(?) time, that's practically the name of the story. And on each occasion, she tried to live differently, accumulating various experiences through every loop. It quickly skips the broken engagement and straight into the hands of ML. It has a nice progression at the beginning, and if I remember correctly. J-novel licensed the LN.
Houseki Shoujo wa Namida o Nagasanai - is a bit of a pain to start reading imo. A lot of abuse and is somewhat random at the start, but it fills out with details as the story progresses.
And I can barely remember the last one. I just know that it exists, it was somewhat fluffy. But considering how many of "villainess"-centric stories I've read, it's a blur.