I know this is a broad subject I just wanted to focus on one aspect: The shulchan aruch (YD 179:19) writes that it is prohibited to study and be taught from a magushi. On what basis do orthodox highschools, even some chardei ones, have non jewish teachers for secular subjects? Is this not a violation of the aformentioned prohibition?
An Amgushi refers to a sorcerer of sorts. The commentaries on the Shulchan Aruch (see Bach, Shach, and others) discuss whether he is specifically a Min (a heretic) or not.
Either way, this halachah will not apply to a run-of-the-mill (non-sorcerer) secular studies teacher.
This is of course the common custom, and provides us with fond memories of the enjoyable or otherwise secular studies lessons we had as young boys.