I am a mail carrier, I open my rear hatch at least 30 times a day. I have recently installed a new latch handle, I purchased a doorman product, however I am on my fourth one. They keep breaking, because the plastic that pushes down to unlock the latch keeps snapping. I have attempted to correct this issue, By heavily greasing all parts, I have even drilled a hole through the plastic push part and inserted a steel rod, this lasted for a while and then snapped at the end of where the steel rod stopped. Do they make these out of metal anywhere? Or has anybody experience The same issue? And have a fix?

I have never seen metal ones. But if you have an unbroken one I'm sure you could have a fabrication/welding/machine shop make a copy out of stainless steel. It would probably be pricey but it could be worth it

A 3D printed part would be cheaper and easier to make. It might even be marketable.

Could it be strong enough? I have very little experience with 3d printed products.

In the beginning, 3D printing was just in plastic resin. Now they can do it in titanium! Airbus makes control surface hinges on a 3D printer that pass FAA regulations! He could have that handle printed in carbon fiber very easily IF he can find someone to do it.

Just a thought. Why not install a solenoid actuator to pop the latch? That would take the stress off the handle. Simple pushbutton on the dash. Many vehicles have that already. As a matter of fact, the WJ uses one to unlatch the liftgate glass with a button under the license plate light bracket.