This barely feels like it fills the 'villainess' flag. This fits a 'fake dating to real dating' type of mold, but while I wouldn't call ditching places and flashy commerce great, I wouldn't call those inherently villainous, either. There also isn't enough time to convincingly establish the sister as an antagonist. This is more of a classic 'scatterbrained girl finds out prince likes her' story. It's not terrible, but it really doesn't do much with the premise - and I feel like I'm only not offended by the poor use of heroine/villainess swap because it's so mediocre that I have a hard time calling them that.
It's not bad, but it sure feels incredibly 'meh'.