Not perfect fix of the rattle problem of the logitech g27, but works way better and less noise. Uploaded a second video for mitigation of another cause of the Problem:
   • Logitech G27 rattle / chatter fix 2.0  

I checked the parts online by now:
The washer is actually just a standard Nylon washer used for M3 screw as seen with part Number "NN-0307-05" under this link: https://de.misumi-ec.com/vona2/detail...

This spring should work:
https://de.misumi-ec.com/vona2/detail...