A cantilever latch from a CAD tutorial is drawn as isotropic plastic. FDM is not. If the arm stands up in Z, the root is a stack of layers waiting to peel.
Print the flex in the XY plane
Lay the arm on the bed so perimeters run the length of the beam. You will need more support under the hook. That is cheaper than reprinting a broken lid.
Taper the arm
A constant-thickness beam dumps all strain at the root. Taper from thick at the wall to thin at the hook. Strain spreads; cycles go up.
Material
PETG for living hinges and snaps that must take a beating. PLA for a first fit only. We do not sell PLA snaps as production hardware.