How to Smooth Out Rough Area on Ceiling Before Painting

My wife and I are fixing up and updating a HiLo we bought a year or so back. We are working on the interior now.

When we were resealing all of the windows, we noticed some of the interior walls and ceiling were super dried out and flaking so we just peeled off what we could. Some of the interior walls we removed entire sections and made a new interior wall. Now, we would like to repaint or put wallpaper or something like on top of the old walls and ceiling.

In the photo, you can see a portion of the ceiling where we peeled away some of the dried out interior wall. What is a good way to smooth out this area before painting? My wife suggested just using spackle and then sanding, like you would for drywall.

Is there a better material to use to smooth out some of these rough areas?

Thank you so much.

Hi Oneros, you have probably already figured out your plan of action, but for a quick (although dusty) fix, I would probably spackle the area and sand smooth. Prime with a good primer/blocker to prevent any bleed-through from the previous leak.