Right Bumper Not Working Anymore: Plastic Piece on Trigger Mount Broke

After about 8 years using the Steam Controller, the right bumper stopped working. It no longer clicks audibly when pressed, even feels that it's floating over the button when fully assembled. I took it apart and found this piece broken off.

That rectangular flange in the red box in the photo needs to be attached to the trigger assembly, but that one narrow path is a point of failure. I don't think I can expect to glue it back on and have it working perfectly fine again. Can I get some advice on finding the part I need to replace this? If it's a 3D print, can I print only part of the base that I need, or do I need a whole new trigger mount assembly, and then move the trigger, spring and bolt there?