Is there in psychology an explanation and/or term that describes the phenomena that exists where people perceive a solution to a problem as “simple” after the solution has been found?
I have noticed in my many years of working with people that there are some who claim the solution to a problem was “simple” - and take great pride in this - but only after the solution has been found.
Of course, many things seem “simple” or “obvious” after they are known.

Example:  Fixing a car.

A mechanic needs to change a part A that only has two screws connecting it to the chassis.  But he has to remove parts B, C, D and E to get to part A, all of which are time- consuming to remove.
After replacing part A the car is fixed.
The boss (who is a mechanic himself but with higher rank within the company) says that the repair was “simple” - just had to change part A.

Is that “oversimplification bias”?  I don’t know if such a bias exists.