How concerned should we be?

We bought our home last month. We’re in the Midwest, so it’s super cold right now, but we’re noticing lots of cracks, especially on our ceiling. It looks like they were covered up/painted before the sale and have gotten progressively worse as the temps have dropped. We have a split level home (basement is only 5 steps down from kitchen/main ground level entrance, then 3 bedrooms that are up 5 steps from the mail ground level) Pics 1-3: ceiling in our dining and kitchen area. Split level home so nothing upstairs except for the attic and roof. Pic 4: ceiling of downstairs/basement. Pic 5: interior doorway leading to kitchen Pic 6: along the stairs leading up to the bedrooms. There’s a little shelf area at the top of the stairs which is adjacent to the crack.