Yea, Libya is 100% Arabic, schools and everything (textbooks) you’ll find in Arabic.
They do have English classes but that starts from 4th grade iirc. Then once you get to college it depends on your degree/courses as there are some which require only English.
I’ve grown up (since born till 9 y/o) only knowing Arabic, then once I went to the US, I didn’t enroll in any Arabic schools so for 7 years all I used was English (Arabic only used at home with my parents) For my little brothers they completely forgot Arabic, I still was able to grasp it a bit but definitely wasn’t good at it.
As for the quran, it was never forced onto me, though I find reading it interesting in either language. Though prefer reading it in Arabic as that’'s the language it was first written in, and translations aren’t always good.