Planes are possibly the most over engineered thing people use regularly, they rarely deal in term of "just enough"

Everything deals in "just enough", otherwise it wouldn't work. Apparently, 119 is the upper limit of how many bolts are "just enough" to fly.

Planes work just fine with 50% of their engine offline. Or with a missing exit door, or with 50% of pilots missing. An airbus will fly with 4 of its 5 control computers offline

If it was "just enough" to complete the mission anything going wrong would become a major issue

Sorry, on what basis are you making the claim that 119 is the lowest bound of what they could get away with just so it can fly? I've never seen that be the case in aircraft, where everything is designed to tolerances way beyond what you'd see in normal or even extreme circumstances.

It's the highest bound, not the lowest bound, as that's how many it has.

Typical safety factor for anything mechanical is >3x, partly for psychological sense of safety and partly to account for model inaccuracies(that isn't to say only every third screws is needed)