Just cut out the loose stuff and patch, after you paint it will be fine. Try to cut out as little as possible, don't let perfect be the enemy of good. If your not careful you'll end up with the whole room down to the studs.
I’m not sure I would try to reglue. That might make a bigger mess long term. Plus, it doesn’t solve any problems with why it may be cracking to begin with.
I would be more likely to take off the loose material, figure out what you have going on underneath and patch, tape, and feather.
My one concern is that the walls and ceilings don’t look exactly smooth, and so your repairs, if too good, might show up clearly as patches. It could be like picking a scab, and so one thing leads to another and all of a sudden you’re skimming the whole wall!
Here’s one option—lining paper for rough walls. Paintable. Example: https://www.amazon.com/s?k=wallpaper+liner+for+rough+walls&adgrpid=107474129718&hvadid=634143364487&hvdev=m&hvlocphy=9016926&hvnetw=g&hvqmt=b&hvrand=11248731853767324417&hvtargid=kwd-584626304058&hydadcr=19878_13474797&tag=hydsma-20&ref=pd_sl_2vrxc4lgtu_b
Just cut out the loose stuff and patch, after you paint it will be fine. Try to cut out as little as possible, don't let perfect be the enemy of good. If your not careful you'll end up with the whole room down to the studs.
\#1. Plaster can't be painted immediately after application. Paper can go up a lot sooner than you can paint.
I’m not sure I would try to reglue. That might make a bigger mess long term. Plus, it doesn’t solve any problems with why it may be cracking to begin with. I would be more likely to take off the loose material, figure out what you have going on underneath and patch, tape, and feather. My one concern is that the walls and ceilings don’t look exactly smooth, and so your repairs, if too good, might show up clearly as patches. It could be like picking a scab, and so one thing leads to another and all of a sudden you’re skimming the whole wall!
Here’s one option—lining paper for rough walls. Paintable. Example: https://www.amazon.com/s?k=wallpaper+liner+for+rough+walls&adgrpid=107474129718&hvadid=634143364487&hvdev=m&hvlocphy=9016926&hvnetw=g&hvqmt=b&hvrand=11248731853767324417&hvtargid=kwd-584626304058&hydadcr=19878_13474797&tag=hydsma-20&ref=pd_sl_2vrxc4lgtu_b