I covered the speaker opening on the back of the Instrument cluster with a little MLV, and foam. I also covered the other openings on the back side with felt.
End result, it muffled the chimes from the instrument cluster, I'd say a 30% reduction in volume, defiantly noticeably quieter. I had contemplated opening the cluster and disconnecting the speaker, but decided against that.

The Carista app has a setting to lower the volume for the turn signal, but this has no effect on my 2013, probably works on later years in this generation.

 

LMAO and here I am, first thing when I did carista was crank that thing up to maximum volume so I could hear it.. Even all the way up it's barely audible.

 

I have a 450h, so engine shuts off at stops and low speed, the car is dead silent except for the clicking and it's louder in my car because it's the hybrid. In your car you have the motor running all the time/also exhaust so that drowns out the clicking from the turn signal.