Hopefully I understand you correctly, but if you are only letting the server do the launch, then I’m not surprised you are seeing lag on the client. Since you are not doing anything on the client, the server launches the character and then later realizes that the client is not in sync with the server (too far from a small error tolerance), so it then corrects the position and velocity of the client to match the server. This is the latency you are seeing.
You can fix this by locally triggering the launch on the client, and then also calling it on the server.
Hope this helps!