Ask HN: My school makes us use Chrome, how do I mitigate privacy loss?

My high school (Lewiston High School, 04240) makes us use Google Chromebooks and unfortunately Chrome just auto-updated to 69. We /have/ to use Chrome and there isn't another option, I tried sideloading app packages (DEB, APK, I tried every type) but it's blocked. Any ideas for mitigating the privacy loss? I know all my data is probably going directly to the school and whatever other government agency cares what I read, I'm just talking in general. At the end of the day everything I do is going to a datacenter, I just don't like it.