Skeptical

The female lead is a transmigrator and she ends up in this action novel (maybe, i dont remember). In the novel theres a male protag and he's also a transmigrator and he transmigrated into a game or a novel with another male protag. The novel male protag doesn't know fl is a transmigrator but fl knows he's one. I remember fl has a system and she can read comments from outside readers. She also has the ability to read the novel she's in and see the changes she's made to the storyline.