The issue is with these stories is the protag changes the timeline completely but still adheres to the game/novel/webtoon like its set in stone.
And by acting like the events in the "original story" will always happen, then end up falling foul the "original story FL" who invariably always becomes new timeline villainess.
I've only read this far, but I kind of hope the "original story FL" Yulia is actually just a nice, friendly person and doesn't want to steal Erin's husband. I know this never happens because these romances always need conflict, but it would be a nice subversion of tropes.