Despair

In my experience, highschool teachers could not be bothered to look over or grade assignments. They would do a lazy “what grade do you think you deserve” essay at the start of the year and carry that grade that you gave yourself through the remaining terms regardless of how much work you did or did not do, even missing that mandatory assignments were skipped.

Some quick solutions would be:
Use cloudflare’s 1.1.1.3 and 1.0.0.3 DNS. At least this works on the device as long as they don’t change the DNS on the device themselves.
https://developers.cloudflare.com/1.1.1.1/setup/#1111-for-families
Parental control settings on your router.