How to turn off the sounds in the Watch Messages app?

One of the great features of the Apple Watch is its discretion: I can receive a message, watch it and respond to it without disturbing others around me with a series of beeps or buzzing vibrations.

However, this is only partially true for the native Messages application: when sending a message, either by selecting one of the predefined answers, such as "yes", "super!", Etc. or by typing an emoji, sometimes (not always) the watch will emit the classic sound of "bwouup" messages from an outgoing message.

I would like to disable the sound of this application, but I have not yet managed to know how. I do not ask how to completely disable the sound of the watch, but rather for sending messages.

What I've tried so far: I've reviewed my iPhone's Watch application messaging settings, as well as the iPhone app settings itself, as well as the sounds and haptics settings. and notifications. The latter allows me to influence the way incoming messages announce themselves, but I have not discovered any parameters for outgoing messages.

Is it possible to disable the sound of outgoing messages in the Watch Messages application?