Upadte 1
I spend some time to improve the model. It needs to be print in PET-G - to get the right elasticity. I also managed to print a working latch by positioning the print horizontally.
Of course this results in having to print the support - for this I have no advice.
I also specifically made an empty space to make the spring element flexible. It will probably wear out over time, but the printout at 0.12 resolution only takes 1.5 hours, so it's bearable.
Update 2
I can confirm that it's been running the same print for almost a year and doesn't look like it's going to break down (it's used every day)
The author marked this model as their own original creation.