This fix was inspired by this design:

https://www.printables.com/model/133723-steam-controller-bumper-repair

It gets attached the same way, but lines up better with the tiny shoulder button and the edge of the steam controller's pcb.

I printed it in PLA with 100% infill and I've found the post-fix feel/action to be very similar to the original. It's very slightly less clicky/a tiny bit mushier, but plenty serviceable.

I don't know how long it will last! It could always be printed in something stronger, or with glass/carbon fiber/whatever filled filament.

The openscad file is basically useless but I'm providing it anyway.

Here's my Bitcoin Cash address if you'd like to buy me a cup of coffee:
bitcoincash:qzm5h2l2945jplwj8r82t393j8plfh9flgg5c66p37

100%