You could just disable the Enabled property after a specific amount of time, and that should work!
Ah! I think it would be better to fire again, back to all clients, and play the sounds there, to avoid the server doing too much and lagging too hard.
Not sure I can do that, since the client script uses a key bind for InputBegan and InputEnded, which means pressing a key and holding it down will continue to emit particles until I release it.
The particles should emit once, and not while holding.
And also, figured out another issue, when I remove the if statement, the sound plays when I press the key, AND release it.