Is this MacBook Air screen fixable?

I inherited a MacBook air 2017 which I want to donate to a school. The computer part seems to work fine however the screen has horizontal lines. At first I thought the damage was due to screen damage but since sometimes it seems to change I'm wondering if it is a loose wire or even an odd software issue. It does display normally on an external monitor connected via display port to HDMI converter so my suspicion of software is much lower. But if it's a loose cable maybe it's worth paying to get it fixed. A new screen will cost at least $250 plus the apple store estimated $450+ for total cost of repair. Otherwise it becomes a desktop. Please advise, thanks in advance!