Consider buying the metal interlock upgrade that is available online. However, I 3D printed a couple of these out of CF PETG and they have lasted several years so far. Make sure the new interlock rotates freely on the shifter assembly and then add some light grease. If printing this out of a filled plastic, the fibers will eventually wear out the plastic without grease.
You will need a short length of 1/8" rod to attach the spring as pictured, which strengthens the part compared to the old OEM design.
The author marked this model as their own original creation.