I can only speak from experience regarding my M1 Air, which has had the whole cracked screen thing when it came out. I have brought it with me to uni and a bunch of other places with and without a sleve and it was fine. If you avoid dropping your backpack (even from low height) and also make sure nothing is putting pressure on the display lid, eveything should be fine. I also have seen people by hardshell cases, which will take some of the pressure of the shell, so that might be worth looking into.

It’ll be far more prtected in a backpack than having a risk of dropping so there’s one way to look at it. Most damage when in backpacks are when it’s in there too tight in between books and such or when a backpack gets casually dropped to the ground or tossed into the corner when you plop it down after lugging it around so you’ll just want to make sure t’s in it’s own sleeve or pocket when in the back pack and no pressure put on it by books and such and don’t forget it’s in there when tossing backpack down. I put my M1 14" in a zippered and padded case and then slide that into the dedicated laptop/tablet etc. pocket of the backpack if it has one, most do… and at the bottom of that pocket I put in a folded piece of this compressed presentation board that’s I cut and folded and taped with black gorilla tape making a 5" tall hollo square reinforcing pocket type of thing… it keeps things from squishing the pocket if that makes sense so it fits in there kinda loose and it’s harder for books and such to compress against it. Might be overkill but I LOVE my 14" protected as I spent 2300.00 on it plus applecare and tax when it first released.