My partner destroyed the rubber buttons on his IX20 keyfob.. I think they just disintegrate after time..
ANYWAY.. I created this replacement.
Just print it in a flexible filament.. (Actually it works fine in just normal PLA).. and probably printing it in black is best!.. Use a 50% infill..
Remove the old rubber buttons (they just pull away)
and then you can either glue the replacement in, or do as I did and use a piece of tape to cover and dust protect it..
Much cheaper than paying a fortune for a new key..