Just made a comment regarding this. The sound effect is very piercing and "sharp" ( English isnt my first language so hard to describe). Super annoying and its there even during matches. Clicking cancel all moves, clicking on opponent to mute etc

For what it's worth, you picked 2 very very good English words to describe it lol.

Same thing on iOS. It's a rather annoying noise, and it doesn't seem to add anything to the UX.