I’m looking for manga: she was reincarnated or pulled in a book - but could see other peoples likeness gauge above their heads. If it fell below 0% she’d die. So she was trying to win favour with her brothers in order to survive( who were quite murderous at the beginning towards her but she noticed the percentage go up in the most surprising moments)
Confirmed in comments, this is Death is the Only Ending for the Villainess/Villains Are Destined to Die. It is a Korean webtoon starring a university student who passes out trying to clear the hard route of a wildly popular Otome game, and wakes up as Penelope Eckhart, the main protagonist of that hard route.
The part where you mention she "could see other peoples likeness gauge above their heads" is the manifestation of a game mechanic, wherein she must raise the affections of those around her so she doesn't end up dying: