what you’re seeing are the edges where the sheets of drywall abut each other.

Yes a bowed wall is dangerous and a sign of bad things happening. As stated that's not what you have.

The dangerous part is the non continuous railing. Also be careful at the winder step

I’m a pro at walking up and down steps so the railings don’t scare me.

I see that exact scenario often in many houses. Mine included. I would guess yours occurs right at the floor line, and they didn't span the drywall sheets over it (or it cracked and was repaired). So you can see the depth of the floor joists, because the floor sheathing stuck out 1/8" past the floor joist, or there's a steel beam and it's open-ended against the drywall. So the drywall bulges with what's sticking out or things have moved (naturally and acceptable) which caused a crack or exacerbated what you see.