Change the toxic emotes so that they are less or not toxic at all.
or
Longer interval between emotes (no spam)
or
No more than x number of emotes more than your opponent (no one-sided emote spamming)
There are certainly players who have fun through being toxic and taunting people, but that's probably not the majority and such taunting comes at a cost of another player. Furthermore, those toxic players probably won't leave the game just because they can't taunt others, but rather those who have been taunted might quit (for a certain amount of time or forever) because of the toxicity.
And really why do we need a "zzz" in game? If it was meant to express opponent being too slow there are numerous better expressions than a "zzz" to express that (like already existing "your go" for example).
Oh, Hello, u can do good stuff as well? 