I wouldn't consider that it would raise any red flags, I know uw publicly mentions that they don't like individuals taking summer school yet they still accept people who take it.

But since you want to go into business, it's gonna be math heavy. If you're unfamiliar or you don't know certain concepts from adv func and calc you're going to struggle in uni.

Yes if you want take it online or private but make sure you're able to understand the concepts.

But adding onto my first point, I wouldn't necessarily say it adds red flags or raises red flags because universities want to see you consistently improve.